So, we will want to use your typical y=mx+b formula. We must find out what m and b equals. m is our slope which is change in y over change in x which is 10/10 which can be simplified down to x (because it’d be 1/1 or just 1 which can just be dropped out of the equation) now that we have m we must find b which is when x=0 and since our slope is 1, we can just take our smallest values given and subtract the x value from both y and x (so 18-20 [the y value] and 20-20 [the x-value so we can get x to equal 0]) and we use the y-value that we are left with to plug in for b which is -2 so your overall equation is
y= x-2
