The slope is the gradient
Gradient = rise/run
Gradient = -1/1
Gradient = -1
Slope = -1
Well.. .not exactly what you're asking, but the relationship of them is

so... hmm to add some
for example let's say
The truck was going 40 miles per hour
The amount of time was 2 hours:
(90-80: 10)(10/2=5)
80 divided by two is 40
The car was going 45 miles per hour
(90-80:10)(10/2=5)
90 divided by two is 45
Hopefully you find this helpful
Answer:
so you divide 16x÷2xy=8/y
which also same as 8y-¹
Y = x + 5....so we sub in x + 5 for y in the other equation
4x + y = 20
4x + x + 5 = 20
5x + 5 = 20
5x = 20 - 5
5x = 15
x = 15/5
x = 3
y = x + 5
y = 3 + 5
y = 8
solution is (3,8)