Answer:
a=2x-b
Step-by-step explanation:

I'm going to out on a limb and say 16 in.
4 pieces * 4 in. = 16
Answer:
the equation for a line is y=MX+b
m= slope(rise/run)
x=variable
b= y intercept
you would find the slope by looking at the rise over run which are both 1 and the line is negative so the slope would be negative one
you would find b by looking at where the y intercept is (y when x is zero) which is 9
y= -x+9
hope that helped