Solve the quadratic equation by factoring. 8x^2+21=-59x

Solve your equation step-by-step.

8x^2+21=-59x

Subtract - 59x from both sides.

8x^2+21--59x=-59x--59x

8x^2+59x+21=0

Factor left side of equation.

(8x+3) (x+7) = 0

Set factors equal to 0.

8x+3=0 or x+7=0

x=-3/8

or

x=-7

Make one side zero

add 59x to both sides

8x^2+59x+21=0

factor

to find the factor in

ax^2+bx+c form when a>1

multiply a and c together

find what 2 numbers add up to b and multiply to ac so

a=8

b=59

c=21

ac=8 times 21=168

factors that add up to 59 and multiply to get 168

the numbers are 56 and 3

3 and 56 are the numbers since 3 times 56=168 and 3+56=168 so

split it up

8x^2+56x+3x+21=0

group

(8x^2+56x) + (3x+21) = 0

undistribute

(8x) (x+7) + (3) (x+7) = 0

reverse distribute

(8x+3) (x+7) = 0

set each to zero

8x+3=0

subtract 3

8x=-3

divide by 8

x=-3/8

x+7=0

subtract 7

x=-7

x=-7 or - 3/8