Help with 7 and 8 and explain

Answer:
7. [tex]44^{\circ}[/tex]
8.
Step-by-step explanation:
7. Using Cosine Rule
[tex]a^2=c^2 +c^2+bcCos(a)[/tex]
=>[tex]a^2=20^2+15^2-2*20*15Cos(68^o)[/tex]
[tex]a^2=400.24[/tex]
[tex]a=20.00[/tex]
=>Using Sine Rule
[tex]20/Sin 68^o=15/sinB[/tex]
[tex]ABC=44^o[/tex]
8