Question

If (x - 1) and (x+2) are the factors of f(x) = 3x³+ax² - bx + 2c then find the value of a+2b -c​

Answer 1

Given,

(x-1) and (x+2) are factors of f(x) = 3x² + ax² - bx +2c

(x - 1)(x + 2) is the required equation

x² - x + 2x - 2 = f(x)

f(x) = x² + x - 2

Given that f(x) = (3+a)x² - bx + 2c

comparing the coefficients of both the equations,

we get

3 + a = 1

a = -2

-b = 1

b = -1

2c = -2

c = -1

Therefore

a + 2b - c = -2 -2 +1 = -3

hope it helps...

Answer 2

Answer is 27. just subtract the two equation. Refer the photo attached