Answer:
4 < x < 14
Step-by-step explanation:
................
Try and become familiar with a program like Desmos. It will do wonderful things for you.
I have graphed
Red: y = -2x + 5 (The 5 is the y intercept. For this question it could be anything.
Blue: y = - 4x + 5 Same note as above.
5.5 gallons
set up a proportion; Liters in numerator and Gallons in denominator
let x = approx number of gallons
<u> 21 </u> = <u> 3.8 </u>
x 1
3.8x = 21
x = 21 ÷ 3.8
x ≈ 5.5