To know if the point(4,2) lies on an equation, we can replace 4 for x and 2 for y and we have to make sure that the result on the left side equals the number on the right side, like this:
1. 5x + 2y=20
5*4+2*2=20
20+4=20
24=20, wrong, 24 is not equal to 20, then the point doesn't lie on this equation.
2. 2x+4y = 16
2*4+4*2 = 16
8 + 8 = 16
16=16, this is correct, then the pint (4,2) lie on the equation 2x+4y = 16
3. x+6y = 16
4+6*2=16
4+12=16
16=16, this is correct, then the pint (4,2) lie on the equation x+6y = 16
4. 3x+3y = 13
3*4+3*2=13
12+6=13
18=13, wrong, 18 is not equal to 13, then the point doesn't lie on this equation.
5. 4x+2y=20
4*4+2*2=20
16+4=20
20=20, this is correct, then the pint (4,2) lie on the equation 4x+2y=20
6. 6x+y=26
6*4+2=26
24+2=26
26=26, this is correct, then the pint (4,2) lie on the equation 6x+y=26
