SOLUTION: if x=-3 is a root of the equation {{{x^3+3x^2-ax-12=0}}}, what is the value of a

SOLUTION: if x=-3 is a root of the equation {{{x^3+3x^2-ax-12=0}}}, what is the value of a

Algebra.Com

Question 378790: if x=-3 is a root of the equation , what is the value of a
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
,
x=-3
plug the value of x
(-3)^3+3(-3)^2-a(-3)-12=0
-27+27+3a-12=0
3a-12=0
+12
3a=12
/3
a=4
...
m.ananth@hotmail.ca
RELATED QUESTIONS
If x=-3 is a root of the equation ((( x^3+3x^2-ax-12=0 ))) then a=... (answered by MathLover1)

Question: Equation: x^3 + ax^2 +bx +a = 0 |a,b are real If x = 2+i is a... (answered by solver91311,ikleyn)

Solve these two equations: (a) The quadratic equation {{{2ax^2-4ax+a+1=0}}} has two... (answered by ikleyn,lotusjayden,MathTherapy)

If one root of a quadratic equation is 3 and the product of the roots is 15, what is the... (answered by ankor@dixie-net.com)

The equation {{{x^4-5x^3-9x^2+ax+b=0}}} has a triple root. Given this root is an integer (answered by Edwin McCravy)

f(x) = (ax^2 + a^2(x) - 2)/(x^3 - 3x + 2) is there a real number of a in which lim x... (answered by Edwin McCravy)

given that x=3+i is a root of p(x)=3x^4+ax^3+34x^2+bx-20 find the value of a and b if... (answered by greenestamps)

y=ax^2-8x-3 x is 2.what is the value of... (answered by Fombitz)

Find the value of k in x^2+3x+k-1=0 if the quadratic equation has: a) equal roots b)... (answered by Fombitz)