3x - 4y = 21
if (7,0) then
3(7) - 4(0) = 21
21 = 21
TRUE
if (-1,-6) then
3(-1) - 4(-6) = 21
-3 + 24 = 21
21 = 21
TRUE
if (-3,3) then
3(-3) - 4(3) = 21
-9 - 12 = 21
-21 = 21 ....-21 can't equal 21
.....this is FALSE
if (11,3) then
3(11) - 4(3) = 21
33 - 12 = 21
21 = 21
TRUE
answer
A, B, D
