SOLUTION: Solve each equation.... (B) x(5x+1)=18 (C) (x-8)(x+6)=15

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Question 443579: Solve each equation....

(B) x(5x+1)=18 (C) (x-8)(x+6)=15
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
(B)
x(5x+1)=18
5x^2+x-18=0
5*-18=-90; 10 and -9 are the two factors of -90 whose sum is 1.
5x^2+10x-9x-18=0
5x(x+2)-9(x+2)=0
(5x-9)(x+2)=0
x=-2, x=9/5
.
Ed