Question

giúp mk với ạ

Answer 1

\(B=3\left(x^2+y^2+2xy\right)-2\left(x+y\right)-100\)

\(=3\left(x+y\right)^2-2\left(x+y\right)-100\)

\(=3.5^2-2.5-100=-35\)

Answer 2

\(B=3x^2+3y^2+6xy-2x-2y-100\)

\(=3\left(x^2+y^2+2xy\right)-2\left(x+y\right)-100\)

\(=3\left(x+y\right)^2-2\left(x+y\right)-100\)

\(=\left(x+y\right)\left(3-2+x+y-100\right)\)

\(=5.\left(-94\right)=-470\)