Question

Can someone explain how to do this problem. I already know the answer, I just want to learn.

1. Solve 5x2 = –45x.

Answer 1

5*2 =10
10=-45x
divide both sides by -45, to isolate x
x=-2/9

Answer 2

since this is a quadratic equation, solve it like a quadratic equation...
get it in standard form, then factor, then use the zero product property to find the solution(s).

Answer 3

is it 5*2 or 5^2?

Answer 4

it is 5x^2

Answer 5

\[5x ^{2}\]

Answer 6

5x^2=-45x
+45x on both sides to balance
5x^2+45x=0
quadratic formula
ithink...

Answer 7

what is the answer?

Answer 8

x=-9

Answer 9

5x^2 + 45x = 0

divide both sides by 5

x^2 + 9x = 0

factor out x

x(x+9) = 0

equate each factor to zero

x = 0

AND

x + 9 = 0

solve for x

Answer 10

ohh yeah, forgot to factor out 5

Answer 11

@destinyshaw there are two answers to this :)

Answer 12

because it's quadratic

Answer 13

the problem is : \[5x ^{2} = -45x\] that is the problem, not it equals 0

Answer 14

wouldn't you use the quadratic formula?

Answer 15

hey, its uj1024, not ujwall, thats a different user

Answer 16

look at the above replies i just continued from there

Answer 17

yeah i deleted lol :P i have bad eyesight

Answer 18

.....I just need to know how to work out this problem :/

Answer 19

quadratic formula is also applicable..both will show same results

Answer 20

Ok, I just tired to work it out.. and it did not work, please someone explain to me in depth