Answer:
x=# of boys
x+7=# of girls
x+x+7=25
2x+7=25
2x=25-7
2x=18
x=18/2
x=9 boys
x+7=16 girls
If you don't understand variables use trial and error.
Boys Girls
1 8
2 9
3 10
4 11
5 12
6 13
7 14
8 15
9 16 9+16=25 students
You could start this way...
Boys Girls
12 13
11 14
10 15
9 16 16 is 7 more than 9
(0,0)(1/3,7/3)
slope = (7/3 - 0) / (1/3 - 0) = (7/3) / (1/3) = 7/3 * 3 = 21/3 = 7 <==
It will be negative 2,cause your equation is already in general form but we can't have a negative on a, so we should changed it on their opposite sign, so 2 will be negative
is equal to 