1) What is the value of x in the equation shown below?
0.25x + 7 = 4(x-2)
Solution
2) What is the rate of change of the linear function that has a graph that passes through the points (2,9) and (-1,3) ?
Solution
Here they asked us to find the rate of change which means slope
also, they have given two pints
When two points are given,
the formula for the slope is,
3) What values of x satisfies the equation -4x -2 / 3 = -6
Solution
4) Which scenario would most likely to show a negative association between the variables?
a) The height of a tree x , and the amount of time it takes to climb to the top of the tree y
b) the number of people in the mall x , and the number of cars in the parking lot y
c) miles traveled in a car x and the amount of gasoline used y
d) time spend reading a book x , and the number of pages left to read y
Solution
Positive association
Two variables have a positive association when the values of one variable tend to increase as the values of the other variable increase.
Negative association
Two variables have a negative association when the values of one variable tend to decrease as the values of the other variable increase.
Option a,b,c are all positive association because if x value increases y also increases and if x decreases y value also decreases.
Ans is option d) time spend reading a book x , and the number of pages left to read y is negative association
because
here, x increases y gets decreases that is,
as we spend more time the pages left decreases
5) Mr. Jones determined that the equation y = 98 - 16/5 x could be used to predict his students' unit test scores,
based on the number of days, x, a student was absent during the unit.
what was the meaning of the y-intercept of the function?
A. A student who was not absent during the unit should score about 98.
B. A student who was not absent during the unit should score about 94.5.
C. A students test score should score increase by about 3.2 points for each day the student is absent.
D. A student test score should decrease by 3.2 points for each day the student is absent.
based on the number of days, x, a student was absent during the unit.
what was the meaning of the y-intercept of the function?
A. A student who was not absent during the unit should score about 98.
B. A student who was not absent during the unit should score about 94.5.
C. A students test score should score increase by about 3.2 points for each day the student is absent.
D. A student test score should decrease by 3.2 points for each day the student is absent.
Solution
Given,
x = number of days absent , y = student unit score
y = 98 - (16/5) x
y-intercept means we have to find y when x=0 in the given equation
x=0 means, No absent days
when x= 0 ,
y = 98 -(16/5) * 0
= 98 - 0
= 98
When x = 0 , y = 98 that is
unit score =98 and No absent days
Hence answer is A) A student who was not absent during the unit should score about 98.
6) In which choice is y a function of x?
A) (1,3) (3,4) (4,5) (5,6)
B) (2,0) (2,3) (4,5) (6,7)
C) (2,5) (4,8) (6,10) (2,12)
D) (6,2) (4,1) (6,8) (8,10)
Solution
y a function of x means , y=f(x)
here, y = output and x = input
y is a function of x says that,
input(x) must be unique values
and each input should have one output value
lets consider option
B) (2,0) (2,3) (4,5) (6,7) [ x has two same values which is 2]
C) (2,5) (4,8) (6,10) (2,12) [x has two same values which is 2
D) (6,2) (4,1) (6,8) (8,10) [x has two same values which is 6]
Hence answer is option A) (1,3) (3,4) (4,5) (5,6)
which has unique x values and each x has y values.
7) A company charges $211.25 for 5 trees and 15 shrubs.The company charges 15.25 more for a tree than a shrub. how much does each shrub cost?
Solution
Given,
5 Trees + 15 Shrubs = $211.25
Tree = 15.25 + Shrub
Now replace Tree by 15.25 + Shrub in the first equation
5 ( 15.25 + Shrub) + 15 Shrubs = 211.25
76.25 + 5 Shrubs + 15 Shrubs = 211.25
76.25 + 20 Shrubs = 211.25
20 Shrubs = 211.25 - 76.25
20 Shrubs = 135
1 Shrub = 135/20 = 6.75
Hence Each shrubs cost $6.75
8) In which choice is y a non linear function of x?
A) x 0 2 4 6 8
y 24 18 12 6 0
B) x 0 2 4 6 8
y 24 18 13 9 6
C) x 0 2 4 6 8
y 24 21 18 15 12
D) x 0 2 4 6 8
y 24 22 20 18 16
Solution
To find whether y is a non linear function of x , we have to find the difference between y values.
If the difference between y values are same then y is a non linear function
Answer : B) , lets find the difference between y values
y 24 18 13 9 6
24-18 = 6
18 - 13 = 5
13 - 9 = 4
9 - 6 = 3 [ the values we got here are difference]
9) Which equation best models the data shown in the scatterplot below?
A) y = 3x+10
B) y=3x+60
C) y=4x+5
D) y=4x+35
Solution
Hence Answer is D) y = 4x+35
10) A car rental company charges $34 per day for a rented car and $0.50 for every mile driven. A second rental company charges $20 per day and $0.75 for every mile driven. What is the number of miles at which both companies charge the same amount for a one-day rental?
Solution
Hence Answer is 56 miles
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