Distribute 4 over (5*a* - 2*b*) to find that 4(5*a* - 2*b*) = 20*a* - 8*b*. Remember how exponent notation works? If not, get a refresher here. If we distribute something that has a variable over a quantity in parentheses that also contains that variable, we use exponent notation to keep things tidy. Probably couldn't hurt to also spray it down with a few squirts of Glass Plus. |