Tuesday, October 26, 2010

Solve the following equations for x and y:1. sqrt(y - 4) = x + 12. sqrt(y + 4) = x + 2

To solve the system of
equations:


sqrt(y - 4)  = x +
1...............(1)
sqrt(y + 4) = x +
2...............(2)


We square the both sides of the
equation (1) and we get:


y-4 =
(x+1)^2.....(1)


We square  both sides of (2) and we get
:


y+4 =
(x+2)^2.....(2).


(2)-(1): 8 = (x+2)^2-(x+1)^2 =
(x+2+x+1)(x+2-(x+1), as (a^2-b^2 = (a+b)(a-b).


=> 8
= 2x+3.


=> 8-3 = 2x.


So
x = 5/2 = 2.5.


Therefore sqrty-4 = (x+1)^2 = 3.5^2 =
12.25.


So y = 12.25+4 =
16.25.


Therefore x= 2.5 and y =
16.25.

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