Two angles that add up to 180 is supplementary
So if the regular price of an item is 25 and the store is marking it up by 40%, then we have to multiply 25 by .4 to find out what 40% of 25 dollars is. 40% of 25 is 10 dollars. So now you just do 25 + 10 and you get 35. Answer: $35
Let's start with y = 4x + b (since 4 is the slope);
We need to find what number should be put instead of b;
Then, let's see what needs to be done;
Plug in the y and x values from the coordinate (22,12) into y=4x+b;
12 = 4(22) + b
Solve;
12 = 88 + b
12 - 88 = b
b = -76
Remember the equation y = 4x + b? Put the -76 instead of b:
y = 4x + -76
or: y = 4x - 76
That is the equation.
To make it standard form, put x and y both in the left side, with x first then y:
-4x + y = -76
^^Answer!
