Linear / Rational / Variable Equations - ACT Math

Card 0 of 20

Question

Undefined_denom3

I. x = 0

II. x = –1

III. x = 1

Answer

Undefined_denom2

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Question

Nosol1

Answer

Nosol2

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Question

Given the following system, find the solution:

x = y – 2

2x – 2y = 2

Answer

When 2 equations in a system have the same slopes, they will either have no solution or infinite solutions. Since the y-intercepts are not the same, there is no solution to this system.

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Question

Find the solution to the following equation if x = 3:

y = (4x2 - 2)/(9 - x2)

Answer

Substituting 3 in for x, you will get 0 in the denominator of the fraction. It is not possible to have 0 be the denominator for a fraction so there is no possible solution to this equation.

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Question

Answer

A fraction is considered undefined when the denominator equals 0. Set the denominator equal to zero and solve for the variable.

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Question

\frac{x+2}{3}=\frac{x}{3} Solve for .

Answer

Cross multiplying leaves , which is not possible.

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Question

Solve:

Answer

First, distribute, making sure to watch for negatives.

Combine like terms.

Subtract 7x from both sides.

Add 18 on both sides and be careful adding integers.

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Question

Solve:

Answer

First, distribute the to the terms inside the parentheses.

Add 6x to both sides.

This is false for any value of . Thus, there is no solution.

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Question

Solve for :

Answer

Like other "solve for x" problems, to begin it, the goal is to get x by itself on one side of the equals sign. In this problem, before doing so, the imaginary -1 in front of (-27x+27) must be distributed.

Once this is done, you may start to try to get x by itself.

However, when subtracting 27x from either side and doing the same on the other, the 27x term cancels out. As a result, the equation becomes:

We know this is an untrue statement because these numbers are 5 spaces away from each other on the number line. The final answer is No Solution.

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Question

Given the following system, find the solution:

Answer

When two equations have the same slope, they will have either no solution or infinite solutions. By putting both equations into the form , we get:

and

With the equations in this form, we can see that they have the same slope, but different y-intercepts. Therefore, there is no solution to this system.

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Question

Solve the following equation for :

Answer

In order to solve for , we must get by itself on one side of the equation.

First, we can distribute the on the left side of the equal sign and the on the right side.

When we try to get by itself, the terms on each side of the equation cancel out, leaving us with:

We know this is an untrue statement, so there is no solution to this equation.

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Question

Solve .

Answer

By definition, the absolute value of an expression can never be less than 0. Therefore, there are no solutions to the above expression.

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Question

In the equation below, , , and are non-zero numbers. What is the value of in terms of and ?

Answer

Pkm_7-21-13

Pkm2_7-21-13

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Question

Linesmb1

Answer

Linesmb5

Linesmb4

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Question

Rational_5

Answer

Rational_2

Rational_3

Rational_4

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Question

John, Jill, and Jack are splitting a pizza. John eats of the pizza and Jill eats of the pizza. How much of the pizza is left for Jack?

Answer

We can write an equation for the amount of pizza eaten, with as the amount left for Jack.

To solve this equation, we must find the lowest common denominator of and . We can list the multiples of and to find the least common multiple:

We can see that the least common multiple of and is , so we can rewrite each of the fractions with a denominator of .

When we put these fractions back into the equation, we can solve for :

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Question

What is the slope of a line represented by the equation:

Answer

To solve problems where you need to find the slope of a line in a given equation, change the equation so that it matches y-intercept form:

For this equation, first move the 3x over to the other side of the equation.

The equation should now look like this:

Then, divide by 15 to isolate the variable .

Then simplify

Whatever number is before the x in the equation (m) is your slope.

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Question

What is the value of (5 + x)(10 – y) when x = 3 and y = –3?

Answer

This is a simple plug-in and PEMDAS problem. First, plug in x = 3 and y = –3 into the x and y. You should follow the orders of operation and compute what is within the parentheses first and then find the product. This gives 8 * 13 = 104. The answer is 104.

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Question

If x = 4, and y = 3x + 5, then 2y – 1 equals

Answer

Start by plugging in x = 4 to solve for y: y = 3 * 4 + 5 = 17. Then 2 * 17 – 1 = 33

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Question

Sarah’s current age is three times Ron’s age two years ago. Sarah is currently 14 years older than Ron. What is the sum of Sarah and Ron’s current age?

Answer

The best way to solve this problem is to turn the two statements into equations calling Sarah’s age S and Ron’s age R. So, S = 3(R – 2) and S = 14 + R. Now substitute the value for S in the second equation for the value of S in the first equation to get 14 + R = 3(R – 2) and solve for R. So R equals 10 so S equals 24 and the sum of 10 and 24 is 34.

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