When a kid of cross the y-axis, the new point has a negative x-coordinate

Sometimes true... if the points x coordinate was originally negative, the reflected points x coordinate is also negative
If it was originally p9s, then the reflected point is pos.
If it starts 0, then it is still 0

On monday,mrs.wise bought 3 lbs of apples at $4per lb= 4*3=$12on tuesday ,20%off and she buy 5 lbs of apples = $4-20%=3.20*5lb=$16example: other wise when she buy 5lbs on monday she have to spend 4*5=20