Tuesday, June 18, 2013

Solve for x : (x+1)^2 = 2x^2 - 5x + 11

The first step is to expand the square from the left side,
using the formula:


(a+b)^2 = a^2 + 2ab +
b^2


(x+1)^2 = x^2 + 2x +
1


We'll re-write the given
equation:


x^2 + 2x + 1 = 2x^2 - 5x +
11


We'll move all terms to the right
side:


0 = 2x^2 - x^2 - 5x - 2x + 11 -
1


We'll combine like terms and we'll use symmetrical
property:


x^2 - 7x + 10 =
0


We'll apply quadratic
formula:


x1 = [7 + sqrt(49 -
40)]/2


x1 = (7+sqrt9)/2


x1 =
(7+3)/2


x1 = 5


x2 =
(7-3)/2


x2 =
2


The quadratic equation has the following
solutions: x1 = 5 and x2 = 2.

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