If (6m − 5n)² = 7 and 30mn = 60, then find the value of (6m + 5n)² + 16mn.
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Correct answer: C
Explanation
Has been given :
(6m − 5n)² = 7
30mn = 60
According to the formula:
(a + b)² = (a − b)² + 4ab
a = 6m, b = 5n
ab = 6m × 5n = 30mn = 60
(6m + 5n)²
= (6m − 5n)² + 4(6m × 5n)
= 7 + 4(60)
= 7 + 240
= 247
(6m + 5n)² + 16mn
= 247 + 16(2)
= 247 + 32
= 279