I'm struggling with these 3 questions. 25 points available if correct.

Answer:
See explanation for answers
Step-by-step explanation:
13.
[tex]y=mx+b\\8=-3(2)+b\\8=-6+b\\14=b\\y=-3x+14[/tex]
14.
[tex]y=mx+b\\4=-\frac{2}{7}(3)+b\\4=-\frac{6}{7}+b\\4\frac{6}{7} =b\\y=-\frac{2}{7} x+4\frac{6}{7}[/tex]
15.
[tex]y=mx+b\\1=\frac{3}{4}(7)+b\\1=\frac{21}{4}+b\\-4.25 =b\\y=\frac{3}{4}x -4.25[/tex]