-2ab
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
The expression 2a x 5b represents the product of 2 times a times 5 times b. This simplifies to 10ab, where 10 is the product of 2 and 5, and a and b are variables that are being multiplied together. This expression cannot be further simplified unless the values of a and b are known.
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-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.
Two negatives make a positive so your equation simplifies firstly as 4ab + 3ab and finally as 7ab.