Question

If a+b=7 and ab=12find the value of (a²-ab+b²)​

Answer 1

(a+b) 2 =a 2+b 2+2ab

7 2 =a 2 +b 2+2(12)

a 2+b 2 =49−24=25

Answer 2

Answer:

(a+b)² = a²+2ab+b²

a+b=7

(a+b)²=7²=49

a²+b²+2ab = 49

ab = 12 ( given in the question)

a²+b²+2×12 = 49

a²+b²+24 = 49

a²+b² = 49-24=25

a²-ab+b² = a²+b²-ab

a²+b² = 25 (solved)

ab = 12 ( given in the question)

so by putting the value

a²-ab+b² = 25-12

a²-ab+b² = 13

so answer is 13