if a + b + c = 7 and ab + bc + ca = 20 find te value of a2 + 2b + c2
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Answered by
3
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
Answered by
1
☺️ 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 ✌️
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