SOLUTION: Help!!! I have no idea how to solve these problems...... Solve: 2x*(x+3) = x+25 and 3x*(x+3) = 2*(5x+1) and (x^2-2x)(x+3) = -2x(x+1)

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Help!!! I have no idea how to solve these problems...... Solve: 2x*(x+3) = x+25 and 3x*(x+3) = 2*(5x+1) and (x^2-2x)(x+3) = -2x(x+1)      Log On


   



Question 150585: Help!!! I have no idea how to solve these problems......
Solve: 2x*(x+3) = x+25
and
3x*(x+3) = 2*(5x+1)
and
(x^2-2x)(x+3) = -2x(x+1)

Found 2 solutions by edjones, Earlsdon:
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
2x(x+3) = x+25
2x^2+6x=x+25
2x^2+5x-25=0
2*-25=-50 what two factors of -50 when added equal 5? 10 and -5
2x^2+10x-5x-25=0
2x(x+5)-5(x+5)=0
(x+5)(2x-5)=0
x=-5,
2x=5 x=5/2
.
3x(x+3) = 2(5x+1)
3x^2+9x=10x+2
3x^2-x-2=0
3*-2=-6 what two factors of -6 when added equal -1? 2 and -3
3x^2+2x-3x-2=0
x(3x+2)-(3x+2)=0
(x-1)(3x+2)=0
x=1
3x=-2 x=-2/3
.
(x^2-2x)(x+3) = -2x(x+1)
x^3+x^2-6x=-2x^2-2x
x^3+3x^2-4x=0
x(x^2+3x-4)=0
x(x+4)(x-1)=0
x=0, x=-4, x=1
.
Ed


Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for x:
1) 2x%2A%28x%2B3%29+=+x%2B25 First, perform the indicated distributive property on the left side.
2x%5E2%2B6x+=+x%2B25 Now combine like-terms by subtracting x from both sides.
2x%5E2%2B5x+=+25 Then subtract 25 from both sides.
2x%5E2%2B5x-25+=+0 Now you have a quadratic equation in standard form that can be solved by factoring.
%282x-5%29%28x%2B5%29+=+0 Apply the zero product rule.
2x-5+=+0 or x%2B5+=+0
If 2x-5+=+0 then 2x+=+5 and x+=+5%2F2
If x%2B5+=+0 then x+=+-5
The solutions are:
x+=+5%2F2
x+=+-5
2) 3x%2A%28x%2B3%29+=+2%2A%285x%2B1%29 First, perform the indicated distributive property on both sides.
3x%5E2%2B9x+=+10x%2B2 Now combine like-terms by subtracting 10x from both sides.
3x%5E2-x+=+2 Then subtract 2 from both sides.
3x%5E2-x-2+=+0 Now you have a quadratic equation that can be solved by factoring.
%283x%2B2%29%28x-1%29+=+0 Apply the zero product rule.
3x%2B2+=+0 or x-1+=+0
If 3x%2B2+=+0 then 3x+=+-2 and x+=+-2%2F3
If x-1+=+0 then x+=+1
The solutions are:
x+=+-2%2F3
x+=+1
Now this should give you enough clues to do the third problem.
If you still have difficulty then please re-post.