Answer:
EF = 32
Step-by-step explanation:
DE + EF = DF
5x - 9 + 2x + 10 = 78
5x + 2x + 10 - 9= 78
7x + 1 = 78
7x = 78 - 1
7x = 77
x = 77/7
x = 11
[tex]EF=2x+10 = 2 \times 11 + 10 \\ EF=22 + 10 \\ \huge \red { \boxed{EF=32}}[/tex]
