Math, asked by nikitajha400, 1 year ago

Find the value of 4x^2+9y^2 if 2x+3y=18 and xy= 5

Answers

Answered by abhi178
103
2x + 3y = 18

take square both sides ,

(2x +3y)² = 18²

4x² + 9y² + 2.2x.3y = 324

(4x² + 9y²) + 12xy = 324

[ given , xy = 5 put it ]

(4x² + 9y²) + 12×5 = 324

(4x² + 9y²) = 324 -60 = 264

hence,
4x² + 9y² = 264

pankaj12je: nah
abhi178: then
pankaj12je: actually in last line there was a typo error 164 instead of 264 :)
abhi178: refresh plz then see
pankaj12je: kk :)
abhi178: refresh plz then see
nikitajha400: Na na 264 is right ans thank u
pankaj12je: kk bro now its 264 awsm answering :-)
abhi178: :-)
nikitajha400: M girl
Answered by pankaj12je
38
Hey there !!!

2x+3y=18-------------Equation 1

squaring Equation 1

(2x+3y)²=18²

4x²+2*2x*3y+9y²=18²

4x²+9y²+12xy=324

But given that xy=5

So,
4x²+9y² =324- 12*5

4x²+9y²= 324-60 = 264

Hope this helped you..................

nikitajha400: Thank u so much
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