Question

Solve the equation by completing the square. Round to the nearest tenth.
x^2+8x=10

A. 1.1, 9.1
B. 1.1, -9.1
C. -1.1, 9.1
D. -1.1, -9.1

Answer 1

what is half of 8?

Answer 2

4

Answer 3

ok good, and what is \(4^2\)?

Answer 4

16

Answer 5

so go right from \[x^2+8x=10\] so \[(x+4)^2=10+16\\
(x+4)^2=26\]

Answer 6

You're trying to find (x+?)^2 that fulfills the requirement of having 8x
this means that the ? is 8/2=4
So now because the ? is 4, and 4^2=16, you add 16 to both sides giving you:
(x+4)^2=10+16
Square root both sides:
\[x+4=\sqrt26\]
subtract 4 from both sides and you have:
\[x=\sqrt26 - 4\]
x=5.10-4
x=-5.10-4
x=1.1 and x=-9.1

Answer 7

take the square root of both sides, don't forget the \(\pm\) get \[x+4=\pm\sqrt{26}\] then a calculator

Answer 8

Thank you guys so much!