Question

On which of the following lines does the point (7, 1) lie?

Answer 1

We have that
the point (7, 1)

case A.) y = 5x + 4
if the point (7, 1) lie to the line
so
for x=7 the value of y must be  1
y=5*7+4------> y=39
39 is not 1---------> the point does not belong to the line

case B.) y = -x + 8
if the point (7, 1) lie to the line
so 
for x=7 the value of y must be  1
y=-7+8------> y=1--------> the point belongs to the line

case C.) y = x - 10
if the point (7, 1) lie to the line
so 
for x=7 the value of y must be  1
y=7-10------> y=-3
-3 is not 1---------> the point does not belong to the line

case D.) y = -4x + 3
if the point (7, 1) lie to the line
so 
for x=7 the value of y must be  1
y=-4*7+3------> y=-25
-25 is not 1---------> the point does not belong to the line

the answer is the option
 B.) y = -x + 8