Please help me! I’m stuck - Mathematics

Answer:
17. 13
18. 3x + 12
19. 1/4
Step-by-step explanation:
17.
[tex]3a + b = 3(5) - 2 \\ = 13[/tex]
18.
[tex]3(x + 4) = 3x + 12[/tex]
19.
[tex]p \: = \frac{3}{3 + 4 + 5 } \\ = \frac{3}{12} \\ = \frac{1}{4} [/tex]
Answer:
Step-by-step explanation:
17. 3(5) + 2 = 15 + 2 = 17
18. 3(x + 4) = 3x + 12
19. 3/(3+4+5)= 3/12= 1/4