C. 4x + y = 21
4(3) + 9 = 21
12 + 9 = 21
21 = 21
Hi,
Work:
Equation;

Root = (0, 0)
Domain: x = R
Vertical Intercept = (0, 0)
Hope this helps.
r3t40
Answer:
10/3 days or 3 1/3 days
Step-by-step explanation:
Let d = number of days total
75% of the days is 10
.75 d = 10
d = 10/.75
d = 40/3 days
We want to know how man is 25% of d
d * 25%
(40/3) *.25
10/3 days
Answer is C. Hope this helped