\(-3x^2-0,5x^2+2,5x^2\)
\(=\left(-3-0,5+2,5\right)x^2\)
\(=-x^2\)
\(5x^3-3x^2+x-x^3-4x^2-x\)
\(=\left(5x^3-x^3\right)-\left(3x^2+4x^2\right)+\left(x-x\right)\)
\(=4x^3-7x^2\)
\(-\dfrac{3}{4}x^3y+\left(-\dfrac{1}{2}x^3y\right)-\left(-\dfrac{5}{8}x^3y\right)\)
\(=\left(-\dfrac{3}{4}-\dfrac{1}{2}+\dfrac{5}{8}\right)x^3y\)
\(=-\dfrac{5}{8}x^3y\)
