SAT Practice Questions (Digital) — All Questions

If x squared = 49 and x is positive, what is the value of x?

• a.5
• b.6
• c.7✓
• d.8

The positive square root of 49 is 7, since 7 x 7 = 49. (The negative solution -7 is excluded because x is positive.)

A square has an area of 64. What is its perimeter?

• a.16
• b.24
• c.28
• d.32✓

The side length is the square root of the area: square root of 64 = 8. Perimeter = 4 x side = 4 x 8 = 32.

If f(x) = x squared - 4x + 3, what is f(1)?

• a.0✓
• b.1
• c.2
• d.-1

Substitute x = 1: f(1) = 1 - 4 + 3 = 0.

A circle has a circumference of 10 pi. What is its radius?

• a.4
• b.5✓
• c.10
• d.20

Circumference = 2 x pi x radius = 10 pi, so 2 x radius = 10 and radius = 5.

If (x + 2)(x - 5) = 0, what is the sum of the two solutions for x?

• a.-7
• b.-3
• c.3✓
• d.7

Set each factor to zero: x = -2 or x = 5. Their sum is -2 + 5 = 3.