Question

 

Answer 1

a: \(3x\left(4x^2-\frac23x\right)\)

\(=3x\cdot4x^2-3x\cdot\frac23x\)

\(=12x^3-2x^2\)

b: \(x\left(x+2y\right)-y\left(2x-1\right)-x^2\)

\(=x^2+2xy-2xy+y-x^2\)

=x

c: \(\left(2x^5+3x^2-4x^3\right):2x^2\)

\(=\frac{2x^5}{2x^2}+\frac{3x^2}{2x^2}-\frac{4x^3}{2x^2}\)

\(=x^3+\frac32-2x\)

d: \(25x^4y^5z^6:\left(-5x^4yz^2\right)\)

\(=\frac{25}{-5}\cdot\frac{x^4}{x^4}\cdot\frac{y^5}{y}\cdot\frac{z^6}{z^2}\)

\(=-5y^4z^4\)

e: \(\left(6x^2+13x-5\right):\left(2x+5\right)\)

\(=\frac{6x^2+15x-2x-5}{2x+5}\)

\(=\frac{3x\left(2x+5\right)-\left(2x+5\right)}{2x+5}=\frac{\left(2x+5\right)\left(3x-1\right)}{2x+5}=3x-1\)