Question

If a + b + c = 12 and a² + b2 + 2 = 64, find the value of ab + bc + ac.​

Answer 1

Answer:

40 is answer

Step-by-step explanation:

40 as(a+b+c)-2 =a2+b2+c2( ab+bc+ca)

144=64+2(ab+bc+ca)

=4o

Answer 2

We know a Algebraic Identity :

(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ac

Substitute The Values

⇒ 12² = 64 + 2ab + 2bc + 2ac

⇒ 12² = 64 + 2(ab + bc + ac)

⇒ 144 = 64 + 2(ab + bc + ac)

Subtracting 64 from Both Sides

⇒ 144 - 64 = 64 + 2(ab + bc + ac) - 64

⇒ 80 = 2(ab + bc + ac)

Dividing Both Sides by 2

⇒ 80/2 = [2(ab + bc + ac)]/2

⇒ 40 = ab + bc + ac