ACT Math : Expressions

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #2 : How To Simplify An Expression

Which of the following expressions are equivalent to b for all non-zero real numbers a, b, x, and y such that  Actmath_43_295_q1

Possible Answers:

Actmath_43_295_a2

Actmath_43_295_a1

Actmath_43_295_a4

None of the answers are correct

Actmath_43_295_a3

Correct answer:

Actmath_43_295_a1

Explanation:

Cross multiply to get 2xb = 3ya2, then divide by 2x to get b on one side of the equal sign by itself.

Example Question #81 : Expressions

A store in California specializes in the sale of custom t-shirts and is growing rapidly. In their second year of business, they doubled the sales from the first year, and in the third year, they sold 50,000 more t -shirts than their second year. In their fourth year, they doubled their sales from the third year. If in the fourth year of business, the store sold 300,000 shirts, how many did they sell in the second year?

Possible Answers:

25,000

100,000

150,000

50,000

250,000

Correct answer:

100,000

Explanation:

This question is a bit wordy, so it is tough to not get lost in it, it usually helps to write down the pertinent information on a separate sheet of paper. In this case, you should have written that year 4 = 2 x year 3 = 300,000

 

so, 300,000 = 2 x year 3

 

divide each side by 2 and we get

 

150,000 sold in year 3. We are told that year 3 = year 2 +50,000

 

so, subtracting 50,000 from each side yields

 

year 3 - 50,000 = total sales from year 2

 

150,000 - 50,000 = total sales for year 2 = 100,000

Example Question #82 : Expressions

Which of the following values is the greatest?

Possible Answers:

28

49

164

82

324

Correct answer:

324

Explanation:

In order to compare each quantity, we need to rewrite each one using the same base. A common base that would be easy to use would be 2, because we can write 2, 4, 8, 16, and 32 all as a power of 2. We also need to remember that when taking an exponent to an exponent, we have to multiple the two exponents together.

 

28 = 28

82 = (23)2 = 26

164 = (24)4 = 216

49 = (22)9 = 218

324 = (25)4 = 220

 

When we compare all of the numbers as powers of 2, we realize that 220 is the largest. Thus, the answer is 324.

Example Question #987 : Algebra

Which of the following expressions is equivalent to 4x2 + 10x – 6?

Possible Answers:
2(2x +1)(x – 3)
2(2x – 1)(x + 3)
(4x + 2)(x – 3)
(2x – 2)(2x + 3)
(2x +1)(2x – 6)
Correct answer: 2(2x – 1)(x + 3)
Explanation:

First, pull out a common factor of 2 to get 2(2x2 + 5x – 3). Then factor the quadratic so that the x terms add to 5x and the numbers multiply to - 3, resulting in 2(2x – 1)(x + 3).

Example Question #988 : Algebra

What is the value of x when 3x + 5 = 2x – 7?

Possible Answers:

–9

–12

12

12/5

5/12

Correct answer:

–12

Explanation:

To answer this question we need to isolate x.  A useful first step is to subtract 5 from both sides.  The expression then becomes 3x = 2x – 12.  Then we can subtract 2x from both sides.  This leaves x = –12.  

Example Question #11 : Simplifying Expressions

Simplify the following expression:

 \dpi{100} \small 2(4x-3x)-6t+5x

Possible Answers:

\dpi{100} \small 7x-6t

\dpi{100} \small 6x+11x

\dpi{100} \small 14x - 11xt

\dpi{100} \small 6t-7x

\dpi{100} \small 1x-6t+5

Correct answer:

\dpi{100} \small 7x-6t

Explanation:

\dpi{100} \small 2(4x-3x)-6t+5x

First distribute the 2:    \dpi{100} \small 8x-6x-6t+5x

Combine the like terms:      \dpi{100} \small 7x-6t

Example Question #24 : How To Do Other Word Problems

f pigeons land on a telephone wire. Then, g+2 pigeons fly away. Find an expression for the number of pigeons remaining.

Possible Answers:

f + g + 2

f - g - 2

2(f + g)

2(f - g)

f - g + 2

Correct answer:

f - g - 2

Explanation:

There are f - g - 2 pigeons remaining on the wire. We start with f pigeons, then subtract (g + 2) pigeons. f - (g + 2) = f - g - 2.

Example Question #1 : Word Problems

Erin is making thirty shirts for her upcoming family reunion. At the reunion she is selling each shirt for $18 apiece. If each shirt cost her $10 apiece to make, how much profit does she make if she only sells 25 shirts at the reunion?

Possible Answers:

Correct answer:

Explanation:

This problem involves two seperate multiplication problems. Erin will make $450 at the reunion but supplies cost her $300 to make the shirts. So her profit is $150.

Example Question #992 : Algebra

Which of the following is equivalent to (x)(x)(x)(x)(x2)?

Possible Answers:

x8

x3

x2

x2

Correct answer:

x2

Explanation:

When multiplying powers of x, we add the exponents. The first four terms are equivalent to x4.

Example Question #12 : Simplifying Expressions

What is \small \frac{2(x^{3}y^{4})+2(x^{2}y^{2})}{(4x^{2})(4y^{2})} in simplified form?

Possible Answers:

\small \frac{xy^{2}}{4}

\small \frac{x^{3}y^{4}+x^{2}y^{2}}{4x^{2}y^{2}}

\small \frac{xy^{2}+1}{8}

\small \frac{x^{2}y^{2}+1}{4}

\small \frac{2xy^{2}+2}{16}

Correct answer:

\small \frac{xy^{2}+1}{8}

Explanation:

Reduce by first dividing all terms by 2:  \small \frac{(x^{3}y^{4})+(x^{2}y^{2})}{8x^{2}y^{2}}

Next divide the terms in the numerator by the two variables in the denominator.  Remember that dividing variables with exponents is really just subtraction of those exponents: \small \frac{xy^{2}+1}{8}

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