Which ordered pair in the form (a, b) is a solution of this equation?
4a – 5b = 24

Normally you use x and y because it is usually (x,y), and not (y,x) so assume a=x and y=b
an easy way is to make one side equal to x then subsitue so
4x-5y=24
add 5y to both sides
4x=24+5y
divide both sides by 4
x=6+5/4y
subsitute and solve

A 6,0 where 6=x and 0=y
6=6+(5/4)(0)
6=6+0
true
A works

B where -2=x and -5=y
-2=-6+(5/4)(-5)
-2=-6-25/4
this is obviously false so B doesn't work

C where x=0 and y=6
0=6+(5/4)(6)
0=6+30/4
0=6+15/2
this is obviously false so C doesn't work

D where x=-5 and y=-2
-5=6+(5/4)(-2)
-5=6+(-10/4)
-5=6-5/2
this is obviously false so D is wrong

if the format is (a,b) or if a=x and b=y then the answer is A,
if the format is (b,a) or if b=x and a=y then the answer is C