Question

[Lê Hoàng Như Quỳnh]

Rút gọn các biểu thức:

a) M+N-P với \(M=2a^2-3a+1,N=5a^2+a,P=a^2-4\)

b) \(2y-x-\left\{2x-y-\left[y+3x-\left(5y-x\right)\right]\right\}\) với \(x=a^2+2ab+b^2,y=a^2-2ab+b^2\)

c) \(5x-3-\left|2x-1\right|\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: M+N-P

\(=7a^2-2a+1-a^2+4\)

\(=6a^2-2a+5\)

b: \(=2y-x-2x+y+y+3x-5y+x\)

\(=-3x+3y-4y+4x=x-y\)

\(=a^2+2ab+b^2-a^2+2ab-b^2=4ab\)

c: \(=\left[{}\begin{matrix}5x-3-2x+1=3x-2\left(x>=\dfrac{1}{2}\right)\\5x-3+2x-1=7x-4\left(x< \dfrac{1}{2}\right)\end{matrix}\right.\)