Answer:
12
Step-by-step explanation:

b - 10 = 7
Take 10 to the other side.

b = 17
Multiply by 4 to isolate b

b × 4 = 17 × 4
4 and 4 cancels out
b = 68
Answer:
a = 1
Step-by-step explanation:
x = 8
3x - y = 9
3(8) - y = 9
24 - y = 9
-y = 9 - 24
-y = -15
y = 15
ax + y = 23
a(8) + 15 = 23
8a = 23 - 15
8a = 8
a = 8/8
a = 1
Answer:
x=5,y=12, area=40 square units
Step-by-step explanation:
the answer is explained in the above picture