Slope intercept form : y = mx + b
4x - 5y < 1
-5y < -4x + 1
y > 4/5x - 1/5 <== slope intercept form
y - x > 3
y > x + 3 <== slope intercept form
Answer:

Step-by-step explanation:
In a right triangle the tangent of an angle is the ratio of the opposite length over the adjacent*. In formulas,
Solving for x, using a calculator for the tangent, 
*I promise I didn't just spellcheck that.
To find the total price, we use this equation:
42 + 0.039(42)
We can make it simpler:
1.039(42)
Multiply:
43.638
Because we're rounding
The total price is $43.64