#### Answer

m=5.7
b= 2m-a
b=-1.9

#### Work Step by Step

Using the equation and plugging in the numbers, we get m=(9.3+2.1)/2. This gives m=5.7.
Now for part b we start by multiplying both sides by 2, to get rid of the denominator. This gives 2m=a+b. Subtracting a, we get 2m-a=b.
For part c, using the numbers they give us the get 2(3.5)-8.9=-1.9, which is b.