Question

What is the value of coefficient c in this quadratic equation?

5x2 + 6x + 7 = 2(x + 2)
A.
7
B.
4
C.
3
D.
-3
E.
3/5

Answer 1

C. 3

Explanation:

`ax^2+bx+c=0\\\\5x^2+6x+7=2(x+2)\qquad\text{use the distributive property}\\\\5x^2+6x+7=2x+4\qquad\text{subtract}\ 2x\ \text{and 4 from both sides}\\\\5x^2+4x+\boxed{3}=0`

Answer 2

C 3

Explanation:

5x^2 + 6x + 7 = 2(x + 2)

Distribute the 2

5x^2 + 6x + 7 = 2x + 4

Subtract 2x from each side

5x^2+6x-2x +7 = 2x-2x+4

5x^2 + 4x + 7 = 4

Subtract 4 from each side

5x^2 +4x+7-4 = 4-4

5x^2 +4x+3 = 0

This is in the form ax^2 + bx +c where c is 3