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Solve for x. Use the completing the square method. x² + 8x = 7

User Ely Dantas
by
5.2k points

1 Answer

3 votes

Answer:
x= -4+ √(23) , or
x= - 4 -√(23)

Explanation:

Let's solve your equation step-by-step.


x^2+8x=7

The coefficient of 8x is 8. Let b=8.

Then we need to add (b/2)^2=16 to both sides to complete the square.

Add 16 to both sides

x^2+8x+16 = 7+16

x^2 + 8x+ 16= 23

Factor left side.

(x+4)^2 = 23

Take the square root.


x+4 = +/- √(23)

Add -4 to both sides.

User Carol McKay
by
5.4k points