Question

If a+b=7 and a^2+b^2 =29, find ab.
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Answer 1

Answer:

we know:-

(a+b)2=a2+b2+2ab

putting respective values:-

(7)2=29+2ab

49-29=2ab

10/2=5=ab

Answer 2

1. Answer:
2. a+b=7
3. squaring both sides ,we get
4. (a+b)^2 = 7^2
5. a^2+b^2 +2ab=49
6. a^2+b^2=49-2ab
7. from1st and 2nd eq we get
8. 29=49-2ab
9. 2ab=49-29
10. 2ab=20
11. ab=20/2
12. ab=10
13. Hence , answer is 10