your equation is linear, so there isn't any arch
Answer:
(27.3692 ; 44.6308)
Step-by-step explanation:
Mean, xbar = 36
Standard deviation, s = 11
Sample size, n = 12
Tcritical at 0.2, df = 12 - 1 = 11 ; Tcritical = 2.718
Confidence interval :
Xbar ± Margin of error
Margin of Error = Tcritical * s/sqrt(n)
Margin of Error = 2.718 * 11/sqrt(12) = 8.6308
Confidence interval :
Lower boundary : 36 - 8.6308 = 27.3692
Upper boundary : 36 + 8.6308 = 44.6308
(27.3692 ; 44.6308)
Solve for x:
x^2 + 4 x + 25 = 0 I ssume that's the notation.
Subtract 25 from both sides:
x^2 + 4 x = -25
Add 4 to both sides:
x^2 + 4 x + 4 = -21
Write the left hand side as a square:
(x + 2)^2 = -21
Take the square root of both sides:
x + 2 = i sqrt(21) or x + 2 = -i sqrt(21)
Subtract 2 from both sides:
x = i sqrt(21) - 2 or x + 2 = -i sqrt(21)
Subtract 2 from both sides:
Answer: x = i sqrt(21) - 2 or x = -i sqrt(21) - 2
