d) If a? + b2 = 9 and ab = 4.
Find the value of 3(a + b)2 – 2(a - b)2
Answers
Answered by
1
Answer:
Step-by-step explanation:
(a+b)²=a²+b²+2ab
=9+2(4)
=9+8=17
(a+b)²=17
(a-b)²=a²+b²-2ab
=9-2(4)
=9-8
(a-b)²=1
3(a+b)²-2(a-b)²=3(17)-2(1)
=51-2
=49
Answered by
6
Step-by-step explanation:
a ²+ b² =9
ab= 4
(a+b)²=a²+b²+2.a.b
=> 9+2×4
=>17
(a-b)² = a²+b²-2.a.b
=> 9-2×4
=> 1
3(a+b)² - 2(a-b)²
=>3×17 - 2×1
=>51 - 2
=> 49
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