Answer:
Step-by-step explanation:
The two will add to 90 degress so
6x+17+3x-17=90 combine like terms
9x=90 divide by 9 to isolate the x
x=10
Now sub it into each equation to solve
ABC = 6(10)+17 = 60+17 = 77
CBD = 3(10)-17 = 30-17 = 13
Check = 77+13 = 90 Correct