Bài 5:
a) Ta có: \(2\left(3x-2\right)+4\left(x+6\right)\)
\(=6x-4+4x+24\)
\(=10x+20\)
b) Ta có: \(2x\left(x-3y\right)+3y\left(2x-5y\right)\)
\(=2x^2-6xy+6xy-15y^2\)
\(=2x^2-15y^2\)
c) Ta có: \(\left(2x-3\right)\left(x+2\right)-\left(4x-2\right)\left(x-5\right)\)
\(=2x^2+4x-3x-6-4x^2+20x+2x-10\)
\(=-2x^2+23x-16\)
d) Ta có: \(4y\left(y+3\right)+\left(y-2\right)\left(y+3\right)\)
\(=4y^2+12y+y^2+3y-2y-6\)
\(=5y^2-13y-6\)
a) Ta có: 2(3x−2)+4(x+6)
=6x−4+4x+24
=10x+20
b) Ta có: 2x(x−3y)+3y(2x−5y)
=2x2−6xy+6xy−15y2
=2x2−15y2
c) Ta có: (2x−3)(x+2)−(4x−2)(x−5)
=2x2+4x−3x−6−4x2+20x+2x−10
=−2x2+23x−16
d) Ta có: 4y(y+3)+(y−2)(y+3)
=4y2+12y+y2+3y−2y−6
=5y2−13y−6
