Question

Tìm đa thức A:

5x\(^2\) - 2A + 4x - 5 = A + 4x\(^2\) - 6x + 7

Answer 1

\(5x^2-2A+4x-5=A+4x^2-6x+7\)

\(\Rightarrow5x^2+2x-5-\left(4x^2-6x+7\right)=3A\)

\(\Rightarrow5x^2+2x-5-4x^2+6x-7=3A\)

\(\Rightarrow x^2+8x-12=3A\)

\(\Rightarrow A=\dfrac{x^2+8x-12}{3}\)

Vậy \(A=\dfrac{x^2+8x-12}{3}\)

Answer 2

3A= 5x²+4x -4x²+6x -7 = x² +10x -7

A = (x² +10x -7)/3