Question

Plz answer step by step....

Answer 1

Answer:

???????????????????..?...????????

Answer 2

Answer:

71

Step-by-step explanation:

Given:

a²+b²+c²=83 and a+b+c=15

To find:

ab+bc+ac=x

Use of formula to solve it:

(a+b+c)²=a²+b²+c²+2(ab+bc+ac)

• a+b+c)²=a²+b²+c²+2x

• 2x= (a+b+c)²-(a²+b²+c²)
• 2x=  15²- 83
• 2x=142
• x=142/2
• x= 71

So,  ab+bc+ac=71 is the answer