Answer:
4 umbrellas
Step-by-step explanation:
Number of Umbrellas Total Money
1 $12
2 $24
3 $36
4 $48
She can't go over $48 because $48 + $12 is $60, which is more than she has ($54). So the max amount of umbrellas she can buy is 4.
y=2.6
y/4=1.3/2
cross product
4*1.3=y*2
5.2=2y
y=5.2/2
y = 4x + 6
-5x - 4x - 6 = 21
-9x - 6 = 21
-9x = 27
x = -3
y - 4(-3) = 6
y + 12 = 6
y = -6
(-3, -6)