Answer:
x=2 √3 − 2 = 1.464101615
x=−2 √3 − 2 = −5.464101615
Step-by-step explanation:
[tex]x^{2}[/tex] + 4x=8
Subtract 8 from both sides of the equation.
x^2 + 4x − 8 = 8 − 8
Subtracting 8 from itself leaves 0.
x^2
+4x−8=0
This equation is in standard form: ax
2
+bx+c=0. Substitute 1 for a, 4 for b, and −8 for c in the quadratic formula,
2a
−b±
b
2
−4ac
.
x=
2
−4±
4
2
−4(−8)
Square 4.
x=
2
−4±
16−4(−8)
Multiply −4 times −8.
x=
2
−4±
16+32
Add 16 to 32.
x=
2
−4±
48
Take the square root of 48.
x=
2
−4±4
3
Now solve the equation x=
2
−4±4
3
when ± is plus. Add −4 to 4
3
.
x=
2
4
3
−4
Divide −4+4
3
by 2.
x=2
3
−2
Now solve the equation x=
2
−4±4
3
when ± is minus. Subtract 4
3
from −4.
x=
2
−4
3
−4
Divide −4−4
3
by 2.
x=−2
3
−2
The equation is now solved.
x=2
3
−2
x=−2
3
−2
