The distributive property: a(b + c) = ab + ac
7 × 7 = 7 × (10 - 3) = (7)(10) - (7)(3) = 70 - 21 = 49
7 × 7 = 7 × (5 + 2) = (7)(5) + (7)(2) = 35 + 14 = 49
Answer:
3a + b = 54
3a + 9 = 54
3a = 54 - 9
3a = 45
3a / 3 = 45 / 3
a = 15