#(2x) / (x + 4) = 3 / (x - 1)#
#2x * (x - 1) = 3 * (x + 4), " cross multiplying"#
#2x^2 - 2x = 3x + 12, " removing braces"#
#2x^2 -2x - 3x - 12 = 0, " bringing all terms to L H S"#
#2x^2 - 5x - 12 = 0, " simplifying"#
#2x^2 - 8x + 3x - 12 = 0#
#2x (x - 4) + 3* (x - 4) = 0#
#(x - 4) * (2x + 3) = 0#
#color(blue)(x = 4, -3/2#