Solve, by factorising, the equation 8x(squared) - 30x - 27 = 0

First, try to see if the 3 terms have a common factor. Yoru equation does not. So u have to multiply the 8x^2 and the 27. That is 216. Then you have to think to yourself, what multiplys to be 216 and adds to be -30? Those numbers are -36 and 6. Now your equation is 8x^2-36x+6x-27=0. Next, factor. What  is both a factor of 8 and 6? That would be 2 and they both have at least one x. So you factor that to get 2x(4x+3). Now the other part. What goes into negative 36x and negative 27 that would be 9 . So when you factor that you get 9(4x-3). They are the same except for the sign and thats easy. That 3 in the second part has to positive to multiply with the -9 to geta -27. So your finally answer is (2x-9)(4x-3).

Ibelieve the total for the tip could be $21.90

Add up all the sides