Let's solve this: I'm going to assume that -7/8x and those similar are (-7/8) times x and so on. from first glance, the fourth equation looks like a failed attempt at a modifier of the first equation. Start: First equation: -(7/8)x - (3/4) = 20 multiply both sides of the equation by -1 to make it the 2nd equation: (7/8)x + (3/4) = -(20)
or to get the third equation from the first, distribute the numerator in -(7/8)x outside the parentheses (remember: top/bottom = top times 1 over bottom) : - 7(1/8)x - (3/4) - 20 equation 4 is weird (lets try to derive the first one from it): -(7/8)(-8/7)x - (3/4) = 20(-8/7) divide to 'get rid' of the (-8/7) -(7/8)x - (3/4)/(-8/7) = 20 first and third terms are right but the second isn't; therefore, the 4th equation is the different one
