1) 6x + 17 = 9x + 2

=> 9x - 6x = 17-2

=> 3x = 15

=> x = 5

2) 7f + 16 = 3f + 48

=> 4f = 32

=> f = 8

3) 4 (c+3) + 10 = -2

=> c + 3 = 8/4 = 2

=> c = 2 - 3 = -1

6x+17=9x+2

6x=9x-15

-3x=-15

x= 5

7f+16=3f+48

7f=3f+32

4f=32

f= 8

4(c+3)+10=-2

4c+12+10=-2

4c+22=-2

4c=-24

c= -6

Gotta get the variable all by itself to solve it. And what you do to one side of the equation, you must do to the other.