17. [tex]2u +5.2 \leq 9.4 + u \\2u - u \leq 9.4 -5.2\\u \leq 4.2[/tex]
18. [tex]3(f+2) > 2f + 4\\3f + 6 > 2f + 4 \\3f-2f > 4-6\\f > -2\\[/tex] The answer is I.
19. [tex]4 < 6b -2 \leq 28\\4+2 < 6b \leq 28+2\\6 < 6b \leq 30\\6/6 < b \leq 30/6\\1 < b \leq 5[/tex]
