Which expression is equlvalent to 7a-8-15a+4

Given abc find the values of x and y. in your final answer, include all of your calculations.

Anew obstacle course is home to several new types of challenging obstacles. one such obstacle is traversing a 15-stair staircase. to make it more challenging, the stairs are not uniformly spaced. rather, the vertical space between consecutive stairs for the first 10 stairs is 113 feet and the vertical space for the last 5 stairs is 134 feet. what is the total vertical distance traveled ascending and descending the entire 15-stair staircase?

11 12 triangle abc is congruent to triangle fde, and both triangles have the same orientation, as shown. what is the slope of df, which is also the slope of ac?