Question

if a + b + c = 7 and ab + bc + ca = 20 find te value of a2 + 2b + c2

Answer 1

Step-by-step explanation:

(a+b+c)²=a²+b²+c²+2(ab+bc+ca)

7²=a²+b²+c²+2(20)

49-40=a²+b²+c²

a²+b²+c²=9

Answer 2

☺️ Heya mate ☺️

Given :-

a + b + c = 7 and ab + bc + ca = 20

Find :-

a² + b² + c²

Solution :-

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

☛ ( 7 )² = a² + b² + c² + 2 ( ab + bc + ca )

☛ 49 = a² + b² + c² + 2 × 20

☛ 49 = a² + b² + c² + 40

☛ 49 - 40 = a² + b² + c²

☛ 9 = a² + b² + c²

Therefore, a² + b² + c² = 9

✌️I hope it helps you ✌️