We muss add the polynomic expression [tex]x^{2}+16\cdot x = -8[/tex] by 64 on both sides.
How to apply the completing the square method to solve a quadratic equation
In this question we must apply the completing the square method to solve a quadratic equation, which consists in apply algebra properties to reduce part of a expression into a square perfect trinomial.
According to the step 2, we have the following expression:
[tex]x^{2}+16\cdot x = -8[/tex] (1)
By applying the principle of compatibility with addition and definition of addition, we have the following expression:
[tex]x^{2}+16\cdot x + 64 = - 8 + 64[/tex]
[tex]x^{2}+16\cdot x +64 = 56[/tex]
Now we proceed to solve the given expression:
[tex](x+8)^{2} = 56[/tex]
[tex]x+8 = \pm 2\sqrt{14}[/tex]
[tex]x = -8 \pm 2\sqrt{14}[/tex]
We muss add the polynomic expression [tex]x^{2}+16\cdot x = -8[/tex] by 64 on both sides. [tex]\blacksquare[/tex]
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