It helps to imagine the variable a sort of as a unit. Like with 5 minus 12 lemons, it has no bearings on the addition/subtraction here.
Factor out a and subtract.
Answer:
y = 1/2x + 3
O f(x)= 1/2x+3
Step-by-step explanation:
f(x) = 2x - 6
y = 2x - 6
x = 2y - 6
2y = x + 6
y = (x + 6)/2
y = 1/2x + 3
Hey boo! The answer is 0.000001. Have a lovely day!
When x=-1:

Ok that gives us a little more information.
If we implicitly differentiate with respect to t, from the very start, then we can apply our product rule, ya?

The right side is zero, derivative of a constant is zero.
Where x' is dx/dt and y' is dy/dt.
From here, plug in all the stuff you know:
y' = -3
x = -1
y = 4
and solve for x'.
Hope that helps!
2 divided by 18 is 9 and 3 divided by 18 is 6 hope that helps