Y = 2x + 5
(7,1)...x = 7 and y = 1
now we sub
1 = 2(7) + 5
1 = 14 + 5
1 = 19...incorrect....NO (7,1) is not a solution
***now if there was a typo and ur set of points are (1,7)
y = 2x + 5
7 = 2(1) + 5
7 = 2 + 5
7 = 7...correct....so (1,7) is a solution
Technically only 1...
If you have to use 4 rows there is only one option;
1 1 1 2
1 1 2 1
1 2 1 1
2 1 1 1
Each number represents the total kids in a row.
1st number is row 1 second number is row 2 etc.
If you can use 2 or 3 rows there are some more answers.
From the attached graphic:
e = c*h/wavelength therefore,
wavelength = c*h / e
wavelength = 299,792,458 * 6.62606957e-34 / 3.38x10^-19
wavelength = 5.8771e-7 meters