Question

Can someone Help me on #9

Answer 1

See Below

Explanation:

If DF = 42, What is DE?

D__________E_______F

(7x + 1) + ( 4x-3) = 42

7x+1+ 4x -3 = 42 Solve for x

11x -2 = 42

+2 +2

11x = 44

11x / 11 = 44/ 11

x = 4

Now plug x in for the equation of DE

7x+1

7(4) + 1

28 + 1 = 29

DE = 19