If 3x -4x=10 and xy=-1,find the value of 9x^2+16y^2

Asked by vishal7979780056 | 12th Aug, 2018, 10:45: PM

Expert Answer:

begin mathsize 16px style 3 straight x space minus space 4 straight y space equals space 10
Squaring space on space both space the space sides comma space we space get
left parenthesis 3 straight x space minus space 4 straight y right parenthesis squared space equals space left parenthesis 10 right parenthesis squared
rightwards double arrow 9 straight x squared plus space 16 straight y squared space minus space 24 xy space equals space 100
we space have comma space xy space equals space minus 1 space
rightwards double arrow 9 straight x squared plus space 16 straight y squared space minus space 24 space cross times space minus 1 space equals space 100
rightwards double arrow 9 straight x squared plus space 16 straight y squared space space equals space 100 space minus space 24
rightwards double arrow 9 straight x squared plus space 16 straight y squared space space equals space 76 end style

Answered by Yasmeen Khan | 13th Aug, 2018, 10:53: AM

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