1) (x+4)(y-5) = xy - 5x + 4y - 202) (a-1)(6-a) = 6a - a^2 - 6 + a = -a^2 + 5a - 63) (5a-7)(3a+1) = 15a^2 + 5a - 21a - 7 = 15a^2 - 16a - 74) (3b+7)(4-3b) = 12 - 9b + 28 - 21b = -9b - 21b + 40 = -30b + 40
1) (x+4)(y-5) = xy - 5x + 4y - 20
2) (a-1)(6-a) = 6a - a^2 - 6 + a = -a^2 + 5a - 6
3) (5a-7)(3a+1) = 15a^2 + 5a - 21a - 7 = 15a^2 - 16a - 7
4) (3b+7)(4-3b) = 12 - 9b + 28 - 21b = -9b - 21b + 40 = -30b + 40