SOLUTION: x^3+3x^2-25x-75=0 Please slove

Question 30145: x^3+3x^2-25x-75=0
Please slove
Answer by sdmmadam@yahoo.com(530) (Show Source): You can put this solution on YOUR website!
x^3+3x^2-25x-75=0 ----(1)
(x^3+3x^2)-(25x+75)=0 by additive associativity
x^2(x+3)-25(x+3) = 0
x^2p - 25p = 0 where p = (x+3)
p(x^2-25) =0
(x+3)(x^2-25) = 0
(x+3) = 0 implies x = -3
(x^2-25) = 0 gives x^2 = 25
Taking sqrt we get x =+5 or x =-5
Therefore Answer: x = -5,-3 and +5
Verification: x =-5 in x^3+3x^2-25x-75=0 ----(1)
LHS = (-5)^3+3X(-5)^2-25X(-5)-75
=-125+75+125-75
=(125-125)+(75-75)
0+0
=0 =RHS
x =5 in x^3+3x^2-25x-75=0 ----(1)
LHS = (5)^3+3X(5)^2-25X(5)-75
=125+75-125-75
=(125+75)-(125+75)
=0 =RHS
x =-3 in x^3+3x^2-25x-75=0 ----(1)
LHS = (-3)^3+3X(-3)^2-25X(-3)-75
=-27+27+75-75
=0 =RHS
So all the values hold

RELATED QUESTIONS
how do you solve... (answered by Tatiana_Stebko)

g(x)=4x^2-3x+1 slove it... (answered by checkley77)

Given: {{{P(x)=x^3-3x^2+25x-75}}} Find all zeros real and... (answered by oscargut)

Solving the following polynomial equation?... (answered by Fombitz)

Please help!!!!!! 1) (3x+14)^2+25=0 2) 25x^2=13 3) 2(x-5)^2=3 4) x^2+4x+4=7 (answered by stanbon)

X^2-25x=0 (answered by checkley79)

-3x^2+25x+24=0 (answered by josgarithmetic)

Plase help me factor this problem: x^3 + 3x^2 - 25x - 75. thank you for your... (answered by Earlsdon)

please slove. 2/3 m =... (answered by THANApHD)