Answer:
x = 1 ±√89
Step-by-step explanation:
We have the equation:
(x+7)(x-9) = 25
Using distributive property:
x(x-9) + 7(x-9) = 25
x²- 9x + 7x - 63 -25 = 0
x²- 2x - 88 = 0
To complete squares we need to add and subtract 1, as follows:
x²- 2x - 88 +1 -1 = 0
x²- 2x +1 -88 -1 = 0 (this is a perfect square)
(x - 1)² - 89 = 0
Solving for x:
(x - 1)² = 89
x - 1 = ±√89
x = 1 ±√89
Answer:
97.75 %
Step-by-step explanation:
You score 1 standard deviation above the mean
a) we have from left tail up to the mean 50 % of all values
b) We have in the interval [ μ - σ ; μ + σ ] 95.5 % of all possible values, if we divide that 95.5 by 2 we get 47.75 %, the part of the values that correspond to the right, then in order to get the % of students scored lower we add
50 + 47.75 = 97.75 %
So you can say that the porcentage of students that scored lower than you is 97.75 %
Answer:
<u>The domain is the set of x-values:</u>
<u>The range is the set of y-values:</u>
This can be a function as each x- value has exactly one corresponding y- value.
