Answer:

Step-by-step explanation:
We need to find the value of x so that the value of given function becomes 21 .
We have ,

Now , for finding x ,
Answer:
30
Step-by-step explanation:
40/100 x 50= 20
50-20=30
Answer:

Step-by-step explanation:
The standard charge includes an initial fee and plus an addditional fee for each mile driven and is given by:

The insurance charge is given by:

So, the total charge C will be the sum of the standard charge S and the insurance charge I:

Substitute:

Rearrange:

Add:

And we have acauired our equation relating C to M!