Answer : x = 20
Explanation :
3x + 2x +20 + 4x - 20 = 180
(3+2+4=9)
9x + 20 - 20
The 20s cancel each other out because one is positive and the other is negative
9x = 180
9x/9 = 180/9
X = 180 divided by 9
X = 20
Given:
n = 20, sample size
xbar = 17.5, sample mean
s = 3.8, sample standard deiation
99% confidence interval
The degrees of freedom is
df = n-1 = 19
We do not know the population standard deviation, so we should determine t* that corresponds to df = 19.
From a one-tailed distribution, 99% CI means using a p-value of 0.005.
Obtain
t* = 2.8609.
The 99% confidence interval is
xbar +/- t*(s/√n)
t*(s/√n) = 2.8609*(3.8/√20) = 2.4309
The 99% confidence interval is
(17.5 - 2.4309, 17.5 + 2.4309) = (15.069, 19.931)
Answer: The 99% confidence interval is (15.07, 19.93)
If xy=0 we assume x and y equal 0
so
the zeros are wehre f(x)=0
0=5(2x-5)(5x+4)
set each to zero
5 is not equal 0 so we don't do that
0=2x-5
5=2x
5/2=x
0=5x+4
-4=5x
-4/5=x
zeroes at x=5/2 and -4/5
Answer:
The difference of squares is (a - b)(a + b) = a² - b². Since a = x and b = 2, the answer is x² - 4.
