-1(7+4b) - distribute the -1 to the expression
(-1 * 7) + (-1 * 4b) — ( + and - = - )when it is multiplied
= -7 - 4b — there is no like term to added to subtracted so it will stay as like
x(x^2 - 2xy+y^2) distribute x to all
= x(x^2) - x(2xy) + x(y^2)
= x^3 - 2x^2y + xy^2 in multiplication exponent add to similar variable
No like term to connect
-5x(-3+x)
= -5x(-3) -5x(+x). (- and - is +)
= 15x -5x. similar variable x so connect the like connect like term by subtracting them
= 10x