Monday, August 17, 2009

Simple quadratic equation

Topic: Quadratic Equation


An equation of the form ax2+bx+c=0 where a, b, c are real numbers and a =/ 0, is called a quadratic equation.

Question:

Solve: x2 - y = 3, x - y = -3

Answer:

x2 - y = 3, x - y = -3

x2 - y = 3

x - y = -3

+ y + y
__________
x = y - 3

Putting this in the first equation

(y -3)x2 - y = 3

y2 - 6x + 9 - = 3

y2 - 6x + 9 - y = 3

y2 - 7y + 9 = 3

-3 -3
____________

Factoring (y - 6) (y -1) = 0

y = 6 on 1

x = y - 3 = 6 - 3 = 3

x = 1 - 3 = - 2

The solution set is : {(-2,1) , (3,6)}

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