two lines have the same non-zero slope and the same y intercept have the property that the sum of their slopes is 0. what is the sum of the x-coordinates of their x-intercepts?

$30 to spend on dinner tax and gratuity at mos restaurant rax is 6% and they give a 15% tip on the total bill after taxes thier dinner cost $21 which statement correctly explains wether andrew and kate have enough money to pay their bill