What are the solutions to the equation completesquare x^2+21x ?

The solutions to the equation completesquare x^2+21x are (x+21/2)^2-441/4

Find the zeros of completesquare x^2+21x

The zeros of completesquare x^2+21x are (x+21/2)^2-441/4

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complete the square

x^{2} + 21 x

(x + \frac{21}{2})^{2} - \frac{441}{4}

Solution steps

x^{2} + 21 x

Write

x^{2} + 21 x

in the form:

x^{2} + 2 a x + a^{2}

2 a = 21 : a = \frac{21}{2}

Add and subtract

(\frac{21}{2})^{2}

x^{2} + 21 x + (\frac{21}{2})^{2} - (\frac{21}{2})^{2}

x^{2} + 2 a x + a^{2} = (x + a)^{2}

x^{2} + 21 x + (\frac{21}{2})^{2} = (x + \frac{21}{2})^{2}

(x + \frac{21}{2})^{2} - (\frac{21}{2})^{2}

Simplify

(x + \frac{21}{2})^{2} - \frac{441}{4}

x^{2} + 12 = 8 x - 4

3 x^{2} + 3 x - 8 = 0

s^{2} - 0.5 s + 0.5 = 0

4 k (k + 3) = - 11

3 x^{2} - 3 x = 9

What are the solutions to the equation completesquare x^2+21x ?
The solutions to the equation completesquare x^2+21x are (x+21/2)^2-441/4
Find the zeros of completesquare x^2+21x
The zeros of completesquare x^2+21x are (x+21/2)^2-441/4