I believe this is the answer
Answer: X=7
Step-by-step explanation: 7 times 3 is 21.
Since there are no actual values, I guess we just have to isolate the b.
2A=bh (multiply both sides by 2)
2A/h=b (divide by h)
hope this helps
6x + 2y = 18
2y = -6x + 18
y = -3x + 9