if (x+2) and (x-2) are factors of ax^4+2x-3x^2+bx-4,then the value of a+b is
Answers
Step-by-step explanation:
(x+2) and (x-2) are factors of ax^4+2x-3x^2+bx-4
Therefore - 2 and 2 are zeros of the polynomial.
When (- 2) is the zero
a(-2)^4+2(-2)-3(-2)^2+b(-2)-4=0
16a-4-12-2b-4=0
16a-2b-20=0
16a-2b=20 - - eq1
When 2 is the zero
a(2)^4+2(2)-3(2)^2+b(2)-4=0
16a+4-3(4)+2b-4=0
16a+2b-12=0
16a+2b=12 - - eq2
Solving eq1 and eq2 by elimination method, we get a=1 and b=-2
Therefore a+b=1-2=-1
Hope it helps...
(x+2) and (x-2) are factors of ax^4+2x-3x^2+bx-4
Therefore - 2 and 2 are zeros of the polynomial.
When (- 2) is the zero
a(-2)^4+2(-2)-3(-2)^2+b(-2)-4=0
16a-4-12-2b-4=0
16a-2b-20=0
16a-2b=20 - - eq1
When 2 is the zero
a(2)^4+2(2)-3(2)^2+b(2)-4=0
16a+4-3(4)+2b-4=0
16a+2b-12=0
16a+2b=12 - - eq2
Solving eq1 and eq2 by elimination method, we get a=1 and b=-2
Therefore a+b=1-2=-1