Equation that works for (3,21) and (21,3)

Step-by-step explanation:

3-21/21-3 = slope

slope =-1

y=-1x+b

21=-3+b

b=24

y=-x+24

a=24; b=12

step-by-step explanation:

a/b=2: 1

a=2b

36/(1+2)=12

b=12

a=24

this linear equation would have just one solution.

step-by-step explanation:

the reason why this would have one solution is that it is an expression with just one variable. since that variable is not raised to a power, it will always have just one solution.