Plug the values into the equation and check if it's true.
\((x,y)=(-9,-12) \\
4 \times (-9) -5 \times (-12) \stackrel{?}{=} 24 \\
-36+60 \stackrel{?}{=} 24 \\
24 \stackrel{?}{=} 24 \\
24 = 24 \\
a \ solution \\ \\
(x,y)=(1,-4) \\
4 \times 1 - 5 \times (-4) \stackrel{?}{=} 24 \\
4+20 \stackrel{?}{=} 24 \\
24 \stackrel{?}{=} 24 \\
24=24 \\
a \ solution\)
\((x,y)=(4,8) \\
4 \times 4 - 5 \times 8 \stackrel{?}{=} 24 \\
16-40 \stackrel{?}{=} 24 \\
-24 \stackrel{?}{=} 24 \\
-24
ot= 24 \\
not \ a \ solution \\ \\
(x,y)=(6,0) \\
4 \times 6- 5 \times 0 \stackrel{?}{=} 24 \\
24 -0 \stackrel{?}{=} 24 \\
24 \stackrel{?}{=} 24 \\
24=24 \\
a \ solution\)
The answers are A, B and D.
