3
10. -16 - 7(2a + 3) = 23 - 2a

Answer:
a=-1.5 (lmk if im incorrect)
Step-by-step explanation:
-16 - 7(2a + 3) = 23 - 2a
-16-(14a+21)=23-2a
5-14a=23-2a
5=23+12a
-18=12a
-18/12 is -1.5
a=-1.5