SOLUTION: Hello, I am old and trying to help my daughter with her physics homework. I have forgotten even the simplest and need a little boost.. 4x^2+12x=0 solve for x thanks, Su

Click here to see ALL problems on Exponential-and-logarithmic-functions

Question 155070: Hello,
I am old and trying to help my daughter with her physics homework. I have forgotten even the simplest and need a little boost..
4x^2+12x=0
solve for x
thanks,
Susan

Found 2 solutions by Fombitz, ptaylor:
Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website!

Factor out an x from each term.

Since the product equals 0, find each individual solution that yields zero.

First solution

Second solution

.
.
.
.
Check your answers with your original equation.

Good answer.

Good answer.

Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website!
IF IT'S ANY CONSOLATION, THERE'S CERTAINLY NOTHING WRONG WITH EITHER (being old and trying to help your daughter, that is)
Since this is a quadratic equation of the form Ax^2+Bx+C where C is zero, we should come up with two values for x.
4x^2+12x=0 looking at the left side, we can factor out a 4x and rewrite as follows:
4x(x+3)=0 now we have
4x=0
x=0
and
(x+3)=0 subtract 3 from each side
x+3-3=0-3
x=-3
So, our answers are x=0 and x=-3
CK
for x=0
4*0^2+12*0=0
0=0
and for x=-3
4*(-3^2)+12+(-3)=0 (note (-3^2)=+9
4*9-3*12=0
36-36=0
0=0
This problem could be solved using the quadratic formula:

Since C is zero, we would have:
or

and

Hope this helps---ptaylor