Question

rút gọn từ đa thức thành nhân tử

\(a.4x\left(4-5\right)+6\left(x-5\right)\)

\(b.2y\left(5x-6\right)-4\left(6-5y\right)\)

\(c.6y\left(x^2-y^2\right)-8y\left(x+y\right)\)

\(d.y^2+10y-9z^2+25\)

\(e.2x^2-xy+2yz-yz\)

Answer 1

\(a)4x\left(x-5\right)+6\left(x-5\right)\\ =\left(x-5\right)\left(4x+6\right)\\ b)2y\left(5x-6\right)-4\left(6-5x\right)\\ =2y\left(5x-6\right)+4\left(5x-6\right)\\ =\left(5x-6\right)\left(2y+4\right)=0\\ c)6y\left(x^2-y^2\right)-8y\left(x+y\right)\\ =6y\left(x-y\right)\left(x+y\right)-7y\left(x+y\right)\\ =\left(x+y\right)\left[6y\left(x-y\right)-7y\right]\\ =\left(x+y\right)\left(6xy-6y^2-7y\right)\\ d)y^2+10y-9z^2+25\\ =\left(y^2+10y+25\right)-9z^2\\ =\left(y+5\right)^2-\left(3z\right)^2\\ =\left(y-3z+5\right)\left(y+3z+5\right)\)