Question

Which is a quadratic equation?

a. y=x+9
b. y=2x-15
c. y=x^2+2x-7
d. y=x^3-x^2

Answer 1

c. y=x^2+2x-7

Explanation:

A linear function has the highest power of 1 (x)

A quadratic has the highest power of 2 (x^2)

A cubic has the highest power of 3 ( x^2)

a. y=x+9 linear

b. y=2x-15 linear

c. y=x^2+2x-7 quadratic

d. y=x^3-x^2 cubic

Answer 2

Quadratic Function is the equation that takes form of:

`\large \boxed{y = a {x}^(2) + bx + c}`

where a, b and c both are real number and a ≠ 0.

The first and second choices are linear equation because it's in the form of y = mx+b.

The last choice is a cubic equation since it has the third degree x³.

Remember that the quadratic equation can be ax²+bx+c = 0 or y = ax²+bx+c only.

Answer

• y = x²+2x-7