Question

Answer 1

a: \(A=2x^4-x^3+7x^2-x+a\)

\(=2x^4+5x^3-6x^3-15x^2+22x^2+55x-56x-140+a+140\)

=(2x+5)(x^3-3x^2+11x-28)+a+140

=>Để A⋮B thì a+140=0

=>a=-140

b: \(A=x^4-x^3+5x+a\)

\(=x^4-2x^3+3x^2+x^3-2x^2+3x-x^2+2x-3\) +a+3

\(=\left(x^2-2x+3\right)\left(x^2+x-1\right)\) +a+3

=>Để A⋮B thì a+3=0

=>a=-3