Question

If m+n=7 and mn=4, find the value of
${m}^{2} + {n}^{2}$
​

Answer 1

41

Step-by-step explanation:

m+n = 7

m×n = 4

(m+n)² = m² + 2mn + n²

= 7² = m² + n² + 2×4

= 49 = m² + n² + 8

= m² + n² = 49-8 = 41

Answer 2

(m + n)^2 = m^2 +n^2 + 2m (7)^2 = m^2 + n^2 + 2×4. (putting the value of m +n and mn inthe equation). 49 = m^2 + n^2 + 8. 49 - 8 = m^2 + n^2. 41 = m^2 + n^2. ANS