Question

if x+1 is a factor of a ax3+2x2-x+3a-7 then find the value of a

Answer 1

X+1=0
Move 1 rightside
x = -1
Let f (x) = ax^3 +2x^2- x + 3a-7
f (-1) = a(-1)^3+2(-1)^2-(-1)+3a-7
0 = a (-1)+2 (1)+1+3a-7
0 = -a +3 +3a -7
0 = -4 +2a
-2a = -4
2a = 4
a = 4/2 = 2

Ans: a=2

Answer 2

Answer:

x+1=0

move 1 rightside

x=-1

let f(x) = ax³+2x²-x+3a-7

f(-1)=a(-1)³+2(-1)²-(-1)+3a-7

0=a(-1)+2(1)+1+3a-7

0=-a+3+3a-7

0=-4+2a

-2a=-4

2a=4

a=4/2=2

answer a=2