A)
y varies inversely as (x-1).
Implies y α 1/(x -1)
y = k/(x-1). Where k is constant of proportionality.
y*(x - 1) = k
when y = 12, x = 1/2
12*(1/2 - 1) = k
12*(0.5 - 1) = k
k = 12*(-0.5) = -6.
k = -6.
Equation connecting x and y
y*(x - 1) = k, recall k = -6
y*(x - 1) = -6
b)
when x = a.
y*(x - 1) = -6
y*(a - 1) = -6
y = -6 / (a -1)
when x = 2a.
y*(2a - 1) = -6
y = -6 / (2a -1)
Difference in y is 1.8
-6 / (2a -1) - -6/(a - 1) = 1.8
-6 / (2a -1) + 6/(a - 1) = 1.8
6 / (a -1) - 6 /(2a -1) = 1.8
6( 1/(a-1) - 1/(2a - 1)) = 1.8
1/(a-1) - 1/(2a - 1) = 1.8/6
1/(a-1) - 1/(2a - 1) = 0.3
((2a - 1) - (a - 1)) / ((a-1)(2a -1)) = 0.3
(2a - 1 -a + 1) /((a-1)(2a -1)) = 0.3
a / (2a² - 3a + 1) = 0.3
a/0.3 = 2a² - 3a + 1
10a/3 = 2a² - 3a + 1
2a² - 3a + 1 = 10a/3
2a² - 3a -10a/3 + 1 = 0
2a² - 19a/3 + 1 = 0
6a² - 19a + 3 = 0
This is a quadratic expression which can be factored.
6a² - 18a - a + 3 = 0
6a(a - 3) - 1(a - 3) = 0
(6a - 1)(a - 3) = 0
6a - 1 = 0 a = 1/6
a - 3 = 0 a = 3.
a = 3 or 1/6
Since a is positive integer, a = 3 only.
Answer:176 psychology textbooks and 98 Biology textbooks were sold.
Step-by-step explanation:
Let x represent the number of psychology textbooks that were sold.
Let y represent the number of biology textbooks that were sold.
textbook store sold a combined total of 274 psychology and biology textbooks in a week. This means that
x + y = 274 - - - - - - - - - - -1
The number of psychology textbooks sold was 78 more than the number of biology textbooks sold. This means that
x = y + 78
Substituting x = y + 78 into equation 1, it becomes
y + 78 + y = 274
2y = 274 - 78
2y = 196
y = 98
x = y + 78 = 98 + 78
x = 176
Answer:
(5sqrt(2), 45 deg)
(-5sqrt(2), 225 deg)
Step-by-step explanation:
(x,y)=(5,5)
So theta=arctan(5/5)=arctan(1)=45 degrees
Now r! r=sqrt(x^2+y^2)=sqrt(5^2+5^2)=sqrt(50)=sqrt(25)sqrt(2)=5sqrt(2)
So one polar point is (5sqrt(2) , 45 degrees)
Now if we do 180+45=225 degrees... this puts us in the 3rd quadrant... to get back to quadrant 1 we just take the opposite of our r
so another point is (-5sqrt(2) , 225 degrees)
13.) 17/20
14.) 11/100
3
16.) 4—
10
17.) 31/4
3
19.) -1–
50
20.) 38
3
22.). -5—
5
3
23.). 1—
25
I don’t know the other ones. Sorry.
Answer:
Step-by-step explanation:
The general form of a quadratic function is:
We'll find the general form of the function:
Multiplying the expressions in parentheses:
Simplifying:
Operating:
