Math, asked by PuruVyas, 10 months ago

if x + 2y = 9 and xy = 7, find the value of x + 4y.​

Answers

Answered by Sriraghava1234567890
1

Answer:

x=2 or 7

y=1 or 7/2

x+4y=53

Answered by malikmohaman
6

xy = 7 \\ x =  \frac{7}{y}

Now put this value of x in x+2y=9

 \frac{7}{y }  + 2y = 9 \\  \frac{7 +  {2y}^{2} }{y}  = 9 \\ 7 +  {2y}^{2}  = 9y \\  {2y}^{2}  - 9y + 7 \\  {2y}^{2}  - 7y - 2y + 7 \\ y(2y - 7) - 1(2y - 7) \\ (y - 1)(2y - 7) \\  \\ y = 1 \: or \:  \frac{7}{2}

Case 1. put y = 1 in x=7/y

x=7

Now put x= 7 and y= 1 in equation x+ 4y

= 7+4×1= 11

Case 2 put 7/2 in x= 7/y

x=2

Now put x= 2 and y= 7/2 in equation x+ 4y

=2 + 4× 7/2 = 2+14 = 16.

Value of x + 4y is 11 or 16

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