4/5 is the answer.
The formula is y=mx+b, where m is the slope
Answer:
21=3(4)+9
Step-by-step explanation:
Assuming that the equation that you are trying the get is y=mx+b, plug in m, x, and b to get:
y=3(4)+9
y=12+9
y=21
Please be more specific so that you get the answer you need
