SOLUTION: Solve the equation by factoring: 4x^2+15x=25 What I did: 4x^2+15x-25=0 (x+20)(x-5)=0 x+20=0 x-5=0 x+-20 x=5

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve the equation by factoring: 4x^2+15x=25 What I did: 4x^2+15x-25=0 (x+20)(x-5)=0 x+20=0 x-5=0 x+-20 x=5      Log On


   

Question 46986This question is from textbook Elementary and Intermediate Algebra: A Combined Course
: Solve the equation by factoring: 4x^2+15x=25
What I did: 4x^2+15x-25=0
(x+20)(x-5)=0
x+20=0 x-5=0
x+-20 x=5 This question is from textbook Elementary and Intermediate Algebra: A Combined Course

Answer by Cintchr(481) About Me  (Show Source):
You can put this solution on YOUR website!
You brought the 25 back onto the side with the other parts, but when factoring, 20 * 5 is not 25 ... you looked for what added to 25 .. not what multiplied to get 25.
+4x%5E2%2B15x=25+
+4x%5E2%2B15x-25=0+
F: 4x * x = 4x^2
O: 4x * 5 = 20x
I: -5 * x = -5x
L: -5 * 5 = -25
+%284x-5%29%28x%2B5%29=0+
+4x-5=0+ and +x%2B5=0+
add five and subtract five
+4x-5%2B5=0%2B5+ and +x%2B5-5=0-5+
+4x=5+ and +x=-5+
Divide by four on the first part
+x=5%2F4+ and +x=-5+
x = {-5, 5/4}