f 5x – 2y = 7 and xy = 2, find the value of (5x + 2y)?
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Answer:
(5x+2y)²=129
Step-by-step explanation:
5x-2y=7
Squaring on both the sides
(5x-2y)²=(7)²
(5x)²+(2y)²-2(5x)(2y)=(7)²
25x²+4y²-20xy=49
25x²+4y²-20(2)=49
25x²+4y²-40=49
25x²+4y²=49+40
25x²+4y²=89
(5x+2y)²
=(5x)²+(2y)²+2(5x)(2y)
=25x²+4y²+20xy
=89+20(2)
=89+40
=129
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