The domain is all real numbers
It’s first 3 letters a,b, and c
3A+2B=20
2A+B=13 ➡×(-2)➡-4A-2B=-26
3A+2B-4A-2B=20-26
-A=-6 ➡A=6
2(6)+B=13➡B=1
Its B.6 because when you plug in 1 for y the equation is 3x-1=17 and you have to cancel out y to get 3x=18 by itself because you have to add 1 to the 17 since you canceled it out of the equation then you are left with 3x=18 and you divide both sides by 3 and then 18 divided by 3 is 6 so x=6
