1)
(7 + x)(y + 3) = 7×y +7x3 +x×y+ x×3
2)
a) (2 + x)(5 + y)
2×5+2×y+x×5+x×y
b) (y + 8)(x + 10)
y×x+y×10+8×x+8×10
c) (x + 8)(1,5 + x)
x×1.5+x×x+8×1.5+8×x
d) (y + 6)(y + 9)
y×y+y×9+6×y+6×9
