Hi,

I don't understand why 2x^2=15-7x has the answer x=-5, 1.5

generally a quadratic EQ will have two roots

2x^2=15-7x 

2x^2 +7x - 15=0

factoring

(2x -3)(x + 5) = 0

(2x -3) = 0   x = 3/2 0r 1.5

(x + 5) = 0   x = -5



 

RELATED QUESTIONS

I don't understand why 2x^2=15-7x has the answer x=-5,... (answered by ewatrrr)

I don't understand this question: 
y=-11x2+bx+c has vertex (−2,5)

a=11         b=?   (answered by ikleyn)

5^n+2 - 5^n+3 = -2500, My teacher solved it like this. I don't understand why we separate  (answered by ikleyn)

my math teacher taught us how to do this but i don't understand (3,2), y = x + 5  (answered by josgarithmetic)

"The gradient of the line joining (4, q) to (6, 5) is twice the gradient of the line... (answered by ikleyn)

i have to graph y=x(1+x)^2 but what i don"t understand is why is it when you foil it  in... (answered by Fombitz)

Correct and explain why this is wrong 0/(-5) = -5 I know the correct answer is 0 but... (answered by MathLover1)

I don;t really understand how to get the answers to these problems, please help.
f(x)=... (answered by solver91311)

What would be the solution for x in the rational equation:

x^2/(x-3) = (x+2)/(2x-5)

 (answered by josgarithmetic)