For the first problem, the solution is as follows:
9y-1/2(4y+20)
1.) Distribute the -1/2 into (4y+20).
9y-2y-10
2.) Combine like terms.
7y-10
3.) Final solution!
7y-10
For the second problem, the answer(s) are solutions A & B.
Solution C cannot be correct because the it does not follow linear algebraic rules (PEMDAS). Solution D is also incorrect because the subtraction sign and division sign change, which does not follow any linear algebraic rules (PEMDAS).
