Answer:
x=35/4
Step-by-step explanation:
S1- Divide both sides of the equation by the same term
-2100=-240x
-2100/-240=-240x/-240
S2- Simplify
DIvide #
Cancel terms
Move the variable to the left
x=35/4
Just to be different we'll start with intercept intercept form which says the line through x intercept (a,0) and y intercept (0,b) is

Through (4,0) and (0,-2) that's

Multiply through by the common denominator of 4 for standard form:
x - 2y = 4
For slope intercept form we solve for y
-2 y = -x + 4
y = (1/2) x - 2
We see our slope is (1/2) and we go through (4,0) so point slope form is
y - 0 = (1/2)(x - 4)
y = (1/2)(x-4)
The 35% is 81.90 plus the 234. So your answer would be $315.90 is the original price. If you need me to explain it let me know :)