Use absolute value. If both signs are negative you will get a negative number. if both are positive you get positive. if the signs are different, subtract the smaller absolute value from the larger absolute value.
You do not want the "b" since two of the equations start off at 0 kites.
x=kites purchased
Kities : y=8x
Windy Kites: y=20x
From there, all you need to do is plug in the kite purchased number replacing x.
<span>149 times 235 is equal to </span>35,015.