evaluate t - u/v when t=2, u= -8 and v = -1/2

simplify -2x-5y- 6x+4y

simplify -5a-3b+8a-b

simplify 7x^3+ 4y^2-9x^3-3y^2

simplify 16x^4-19x^4-8y^3-7x^4

simplify (-4x^2+3y-8)+(-5y-2x^2+1)

simplify (-3a^3+ 7b ^2)-(-6a^3+9b^2)

simplify (5-p^2-4q)-(-2-q-3p^2)

simplify -3(4h^5-k^4)=(5k^5+2k^4)

simplify -(9w^3-2z+3)+4(3w^3-z)

simplify -6(w^3-3z+4)-2(7z-5w^3)