Math Flashcards

If 3x − 7 = 2x + 5, what is the value of x?

Answer: 12

Subtracting 2x from both sides gives x − 7 = 5, so x = 12.

A store sells notebooks for $3 each and pens for $1.50 each. Maria bought 10 items for $22.50. How many notebooks did she buy?

Answer: 5

Setting up n + p = 10 and 3n + 1.5p = 22.50, then solving gives n = 5.

Which value of x satisfies 2|x − 3| ≤ 8?

Answer: x = −1

Dividing by 2 gives |x − 3| ≤ 4, which means −1 ≤ x ≤ 7, so x = −1 satisfies this.

A line passes through (2, 5) and (6, 13). What is the y-intercept of this line?

Answer: 1

The slope is (13 − 5)/(6 − 2) = 2; substituting (2, 5) gives 5 = 2(2) + b, so b = 1.

A car travels 240 miles on 8 gallons of gas. At this rate, how many gallons are needed for 360 miles?

Answer: 12

The car gets 30 mpg, so 360 miles requires 360 ÷ 30 = 12 gallons.

What is the value of 2³ × 4² ÷ 8?

Answer: 16

2³ = 8 and 4² = 16, so 8 × 16 ÷ 8 = 16.

If f(x) = 4x − 9 and f(k) = 7, what is the value of k?

Answer: 4

Solving 4k − 9 = 7 gives 4k = 16, so k = 4.