Answer:
y = 75 - x
Explanation:
From the question, we are given variables, and then we can see that
when x = 75 then y = 0
when x = 30 then y = 45
Finding the difference, we have
slope(m) = (45 - 0) / (30 - 75)
slope(m) = 45 / -45
slope(m) = -1
Next, we use the calculated m, to find b, using the formula
y = mx + b
0 = -1 * 75 + b
0 = -75 + b
b = 75
And finally, to get the needed equation, we say that
so y = mX+c
So that
y = -1 * x + 75
y = -x + 75
or y = 75 - x