The answer would be a = 1.
Here are the steps i did.
1. Simplify 43a + 10 - 26a to 17a + 10 ( 17a + 10 = 27 )
2. Subract 10 from both sides ( 17a = 27 - 10 )
3. Simplify 27 - 10 to 17 ( 17a = 17)
4. Divide both sides by 17 ( So in conclusion the answer would be a = 1.)