5x - 9 ≤ 21
5x ≤ 21 + 9
5x ≤ 30
x ≤ 30 ÷ 5
x ≤ 6
Both terms have a

in common, so we can pull it out. The factored form will be

times whatever is left after pulling it out.
In the first term, we will have just 8 left since everything else in the term is factored out.
The second term has a

left. Notice that both of these terms no longer have a negative sign since the negative was factored out.
The answer is
Divide everything by 4 getting:
7y=3x+21
then get all of the variables on one side by subtracting 3x:
7y-3x=21
The answer should be -4,
7x2=14
2x-9=-18
14+ -18= -4
3.14/5.71=0.18330414466 years
hope this hepls