Question

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

Answer 1

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

Answer 2

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