polynomials

(1) find the dividend if the divisor is 3x-4 , quotient = 2x-5 and remainder = -6

Let the dividend be f(x)

f(x) = (3x-4)(2x-5) + (-6)
f(x) = 10x²-8x-15x+20-6
f(x) = 10x²-23x+14

(2) find the divisor if the dividend is 3x^2 + 4x - 7, quotient = x+2 and remainder = -3

Let the divisor be D(x)

3x² + 4x - 7 = D(x)(x+2) + (-3)
3x² + 4x - 4 = D(x)(x+2)
D(x) = (3x² + 4x - 4)÷(x+2)
D(x) = (3x-2)(x+2)÷(x+2)
D(x) = (3x-2)

2014-03-01 15:36:11 補充：
(1) find the dividend if the divisor is 3x-4 , quotient = 2x-5 and remainder = -6

Let the dividend be f(x)

f(x) = (3x-4)(2x-5) + (-6)
f(x) = 6x²-8x-15x+20-6
f(x) = 6x²-23x+14