Answer:
$20
Step-by-step explanation:
Total cost of items bought
= $31.21 +$12.75 +$13.25
= $57.21
Remaining cost after paying $40
= $57.21 -$40
= $17.21
Amount borrowed
= change +$17.21
= $2.79 +$17.21
= $20
Perpendicular means the slopes are opposite inverse of each other
If line a is slope 2, the perpendicular line to Line a would have a slope - 1/2
Difference in y over difference in x gives slope. If they are opposite inverse values the lines are perpendicular. ( in this case the answer is true.)
