1: \(2x\left(3+5x-xy\right)=2x\cdot3+2x\cdot5x-2x\cdot xy=-2x^2y+10x^2+6x\)
2: \(\left(y-1\right)\left(y+2+5\right)=\left(y-1\right)\left(y+7\right)\)
\(=y^2+7y-y-7=y^2+6y-7\)
3: \(\left(3+x\right)^2-5x+2\)
\(=x^2+6x+9-5x+2\)
\(=x^2+x+11\)
4: \(6y-\left(4-y\right)^2\)
\(=6y-\left(y^2-8y+16\right)\)
\(=6y-y^2+8y-16=-y^2+14y-16\)
5: \(\left(x+y\right)\left(x-y\right)-3x^2=x^2-y^2-3x^2=-2x^2-y^2\)
6: \(\left(x-7\right)\left(x+7\right)-\left(x+3\right)^2\)
\(=x^2-49-x^2-6x-9\)
=-6x-58
7: \(\left(x+2\right)^2-\left(1+x\right)\left(1-x\right)\)
\(=x^2+4x+4-\left(1-x^2\right)\)
\(=x^2+4x+4-1+x^2=2x^2+4x+3\)
8: \(\left(x+7\right)\left(3-x\right)=3x-x^2+21-7x=-x^2-4x+21\)
9: \(\frac32xy\left(4xy+2-x^2y\right)=\frac32xy\cdot4xy+\frac32xy\cdot2-\frac32xy\cdot x^2y\)
\(=6x^2y^2+3xy-\frac32x^3y^2\)
10: \(\left(1-7x^2y^3-x^2y\right)\left(-2xy^2\right)\)
\(=-2xy^2\cdot1+2xy^2\cdot7x^2y^3+2xy^2\cdot x^2y\)
\(=-2xy^2+14x^3y^5+2x^3y^3\)
