If you are asking how to subtract 125 centimeters and make it 87.5, you have to subtract from 125. The easiest way to do this is to subtract 87.5 from 125, getting 37.5. So, if you add 37.5 to 87.5, you will have 125. So, the correct answer is to subtract 37.5 to get 87.5.
The lenght of your ruler is 6inches or approximately 15cm.
Answer:

Step-by-step explanation:
Equation of a line is given as:
y = mx + b
Where
m is the slope
and
b is the y-intercept (y-axis cutting point)
Since we know slope is -4, we can write:
y= mx + b
y = -4x+ b
Given the point (-2,7) , we can say:
x = -2
and
y = 7
Plugging these 2 values, we can solve for b:
y = -4x + b
7 = -4(-2) + b
7 = 8 + b
b = 7 - 8
b = -1
Now, we have the equation:
