Answer:
a = 18
Step-by-step explanation:
2(a-7)=a+4
Distribute 2 into left side: 2a -14 = a + 4
subtract a from both sides 2a-a-14 = a+4-a
Simplify: a - 14 = 4
Add 14 to both sides: a - 14 + 14 = 4 +14
Simplify: a = 18
If wanted, plug a into original to double check work:
plug in: 2 (18-7) = 18+4
do parenthesis first: 2 (11) = 18+4
do multiplication : 22 = 18+4
additions: 22 =22
a = 18 is correct.
3 + 2 = 1 + 4
2 + 15 = 10 + 7
8 + 9 = 19 - 2
12 - 7 = 14 - 9
Hope this helped!
1. 12a+6=12a+6
2. 12a+6=12a+2
3. 12a+6=4a+6
4. 12a+6=7a+5
Answer:

Step-by-step explanation:
we know that
The formula of law of cosines is equal to

where
a, b and c are sides. C is the angle opposite side c
In this problem we have

substitute the given values





