Answer:
7. n = 5r + 10
9.
Explanation:
7.
The table gives you these values
2 20
4 30
6 40
8 50
The left side goes up by 2 each time while the right side goes up by 10 each line.
Using that pattern, fill in a few extra lines. I did it below in bold.
0 10
1 15
2 20
4 30
6 40
8 50
The line 0, 10 shows you that b in y = mx + b is 10. Also from the fist line to the second line, as x goes from 0 to 1, a difference of 1, y goes from 10 to 15, a difference of 5. The slope is difference in y over difference in x, so
slope = m = 5/1 = 5.
The equation is
y = mx + b
y = 5x + 10
The problem uses n instead of y and r instead of x, so you get
n = 5r + 10
9.
One pair of jeans costs $28.50. j is the number of jeans. j number of jeans cost 28.50j.
One shirt costs $18. s is the number of shirts. s number of shirts cost 18s.
The total cost is the cost of the jeans plus the cost of the shirts.
The total cost is 28.50j + 18s.
She can spend up to $100. The total cost of the jeans and shirts can be less than $100 or exactly $100, but it cannot be more than $100.
cost of jeans and shirts must be less than or equal to $100