(-7,1) is a solution to the inequality y<0.5x+9
Let x = times in the pool
Let y = times in the basketball courts
42=3x+5y
x+y=12
Therefore y = 12-x
Subsitute for y
42 = 3x + 5(12-x)
42 = 3x + 60 -5x
Subtract 60
-18 = -2x
9 = x
The person used the pool 9 times.
If a number is positive, Leila's theory that 75% of a number will always be greater than 50% of another number is <em>true</em>;<em> </em>however, if both numbers are negative, or if the number of which she finds 50% is much greater than the number of which she finds 75%, Leila's theory could be incorrect.
This inequality shows that Leila is correct:

(which simplifies to

)
This inequality shows that Leila is incorrect:

(which simplifies to

)
Hope this helps!