Saturday, September 15, 2012

Solve the system of equations algebraically: y=x^2+4 y=2x+7

We have to solve the system of
equations:


y=x^2+4


y=2x+7


Equate
the value of y


=> x^2+4 =
2x+7


=> x^2 - 2x - 3 =
0


solving the quadratic equation we get two values of
x.


=> x^2 - 3x + x - 3 =
0


=> x(x - 3) + 1(x - 3) =
0


=> (x - 3)(x + 1) =
0


Or x = 3 and x = -1


For x =
3, y = 2x + 7 = 13


For x = -1, y = 2x + 7 =
5


Therefore the required solution is


( 3 , 13) and ( -1 ,
5)

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