how do you graph f(x)=−4+7x
f(x) just means that y=-4+7x for a certain value of x.
for example, f(0) would be -4 because
y= -4+7(0) =
-4+0 =
-4
you plug in a value of x and solve to get y.
(or just use desmos)
Hope this helps!
+10 
