Question

giúp mk vs 

A=x(x+y)-5(x+y) với x=1;y=2

Answer 1

\(A=\left(x-5\right)\left(x+y\right)\) thay vào:

\(A=\left(1-5\right)\left(1+2\right)=-4.3=-12\)

Answer 2

\(A=x\left(x+y\right)-5\left(x+y\right)=\left(x+y\right)\left(x-5\right)\)

\(=\left(1+2\right)\left(1-5\right)=3.\left(-4\right)=-12\)

Answer 3

\(A=x\left(x+y\right)-5\left(x+y\right)=\left(x-5\right)\left(x+y\right)\)

Thay x=1 và y=2 vào A ta đc:

 \(A=\left(1-5\right)\left(1+2\right)=-4\cdot3=-12\)

Answer 4

\(=\left(x+y\right)\left(x-5\right)=\left(1+2\right)\left(1-5\right)=-12\)