1) (c-4)(d-3) = cd - 3c - 4d + 12
2) (a-10)(-a-2) = -a^2 - 2a + 10a + 20 = -a^2 + 8a + 20
3) (x+y)(x+1) = x^2 + x + xy + y = x^2 + x + y(x+1)
4) (-p+q)(-1-q) = p + q + pq + q = p + q + q(p+1)
1) (c-4)(d-3) = cd - 3c - 4d + 12
2) (a-10)(-a-2) = -a^2 - 2a + 10a + 20 = -a^2 + 8a + 20
3) (x+y)(x+1) = x^2 + x + xy + y = x^2 + x + y(x+1)
4) (-p+q)(-1-q) = p + q + pq + q = p + q + q(p+1)