If s represents the number of songs Kim downloads, her expenses for a month must satisfy the inequality
5.00 + 0.58·s ≤ 13.00
To solve this, subtract 5.00 to get the s-term by itself, then divide by the coefficient of s.
0.58·s ≤ 8.00
s ≤ 8.00/0.58 ≈ 13.79
The number of songs must be an integer, so we conclude Kim can download 13 songs, but not 14 songs.
Kim can download 13 songs without exceeding her budget.
Here is your answer and an explanation
Answer: y = -2/3x
Explanation:
This can be determined by calculating the gradient of the straight line, using:
m=ΔyΔx
=−6−34−(−2)
=−96
=−32
Then we use the slope-point form of the straight line:
y−y1=m(x−x1)
to give:
y−3=−32(x−(−2))
∴y−3=−32(x+2)
∴y−3=−32x−3
∴y=−32x
Number of weekend minutes used: x
Number of weekday minutes used: y
This month Nick was billed for 643 minutes:
(1) x+y=643
The charge for these minutes was $35.44
Telephone company charges $0.04 per minute for weekend calls (x)
and $0.08 per minute for calls made on weekdays (y)
(2) 0.04x+0.08y=35.44
We have a system of 2 equations and 2 unkowns:
(1) x+y=643
(2) 0.04x+0.08y=35.44
Using the method of substitution
Isolating x from the first equation:
(1) x+y-y=643-y
(3) x=643-y
Replacing x by 643-y in the second equation
(2) 0.04x+0.08y=35.44
0.04(643-y)+0.08y=35.44
25.72-0.04y+0.08y=35.44
0.04y+25.72=35.44
Solving for y:
0.04y+25.72-25.72=35.44-25.72
0.04y=9.72
Dividing both sides of the equation by 0.04:
0.04y/0.04=9.72/0.04
y=243
Replacing y by 243 in the equation (3)
(3) x=643-y
x=643-243
x=400
Answers:
The number of weekends minutes used was 400
The number of weekdays minutes used was 243
Malaria proved that the equation you need to add the parenthesis first
