Answer:
a) yx=63
b) y=3
Step-by-step explanation:
a)
yx=k (inverse formula)
7(9)=k
63=k
b)
y(21)=63
y=63/21
y=3
Answer: It would make the meal $40.00 and with tax it would be $42.80
Step-by-step explanation: 50 - 10 = 40
40 / 0.07 = 2.8
40 + 2.8 = 42.8