How do you factor #2x ^ { 2} + 21x = - 40#?

1 Answer
Apr 6, 2018

Answer:

the answer is #x=-8 & x=-5/2#

Explanation:

first add #40# to both sides to make it equal to #0# and now you get #2x^2+21x+40=0# now find two numbers that multiply to give you #80(2*40)# and add to give you #21# you get #16,5# and now you put it in #2x^2+16x+5x+40=0# now group then and take out what you can and you'll get #2x(x+8)+5(x+8)# the two parenthesis have to be the same. now you have #(2x+5)(x+8)# but since it's equal to #0#, you have to solve. so now you set them both to #0# and you just solve for #x# and you get your answer