Answer is -4
Step by step
We know the slope is 1x so for every 1 input we have 1 output. We can graph it and find the y intercept (attached)
We can also find “b” the unknown, we can use one set of points (10, 6) the slope of 1 and the formula
y - y1 = m (x - x1)
y - 6 = 1 ( x - 10)
Multiply
y - 6 = x - 10
Add 6 to both sides to isolate y
y -6 +6 = x -10 +6
Simplify
y = x -4
Again, -4 is our answer