-8
7a-b=15a Subtract 7a from both sides
-7a -7a
-b=8a
-b/8=8a/8 Divide each side by 8
-b/8=a Solve
-2ab
7ab
The LCM is 280a4b2.
5a(a(a-5)+3)
It's not always to 'solve' as it is to 'simplify' EX: 15a + 3b = 45c simplifies to 5a + b = 15c
Add 54 to both sides and you get 15a = 45. I think a chimp could solve this one. (a=3)
-2ab
If you mean: 15a = 6a - 90 then the variable a works out as -10. If you mean 15a + 6a - 90, then it equals 21a - 90.
7ab
7ab-5ab = 2
7ab itself
The LCM is 280a4b2.
7b
5a(a(a-5)+3)
It's not always to 'solve' as it is to 'simplify' EX: 15a + 3b = 45c simplifies to 5a + b = 15c
35ab
x would be 5.