Question

Mulțumesc anticipat!

Answer 1

a)
b + c = 4
ab + ac = 12

ab + ac = 12
a(b + c) = 12
4a = 12
a = 3

b)
b - c = 5
ab - ac = 20

ab - ac = 20
a(b - c) = 20
5a = 20
a = 4

c)
a = 6
ab - ac = 24

ab - ac = 24
a(b - c) = 24
6(b - c) = 24
b - c = 4

d)a = 5
2a + 3b + 3c = 40

2 × 5 + 3b + 3c = 40
10 + 3b + 3c = 40
3b + 3c = 30
3(b + c) = 30
b + c = 10

a^2 + ab + ac =
a(a + b + c) =
5(5 + 10) =
25 + 50 =
75