Answer:
A) 12
You know:
AB= 3x
AB= 3xAC= 17
AB= 3xAC= 17BC= 2x-3
Therefore, you can put the values in a number line for reference. By doing this you can see that 3x + 2x -3 (or AB +BC) = 17 (or AC)
From here you can set up the equation to be:
17 = 2x - 3 + 3x
and solve for x by combining like terms:
17= 5x-3
adding 3 to both sides:
20=5x
dividing each side by 5:
20/5=5x/5
to get:
x=4
then, you're gonna plug in your x (4) into 3x (your AB) in order to solve for AB:
AB=3x
AB=3x =3(4)
AB=3x =3(4) =12
therefore, your answer is:
AB = 12
