Well I don't know if you are looking for the variable but here it is :)
Owner would lose out on $100
Let s=number of seeds and t=number of days...
st=120 and (s+10)(t-2)=120
From the first we can say t=120/s, now using this value of t in the second equation gives us:
(s+10)(120/s-2)=120
(s+10)(120-2s)/s=120
(s+10)(120-2s)=120s
120s-2s^2+1200-20s=120s
2s^2+20s-1200=0
s^2+10s-600=0
(s+30)(s-20)=0, since s>0
s=20, and since she planted s+10 seeds per day to finish two days earlier:
20+10=30
She planted 30 seeds per day.
Answer:
3. 
2<em>C.</em> 
2<em>B.</em> 
2<em>A.</em> 
1. ![\displaystyle Set-Builder\:Notation: [x|7, 0 ≠ x] \\ Interval\:Notation: (-∞, 0) ∪ (0, 7) ∪ (7, ∞)](https://tex.z-dn.net/?f=%5Cdisplaystyle%20Set-Builder%5C%3ANotation%3A%20%5Bx%7C7%2C%200%20%E2%89%A0%20x%5D%20%5C%5C%20Interval%5C%3ANotation%3A%20%28-%E2%88%9E%2C%200%29%20%E2%88%AA%20%280%2C%207%29%20%E2%88%AA%20%287%2C%20%E2%88%9E%29)
Step-by-step explanation:
3. <em>See</em><em> </em><em>above</em>.
2<em>C</em>. The keyword is ratio, which signifies division, so you would choose "III.".
2<em>B</em>. The keyword is percent, which signifies multiplication of a ratio by 100, so you would choose "I.".
2<em>A</em>. The keyword is total, which signifies addition, so you would choose "II.".
1. Base this off of the denominator. Knowing that the denominator CANNOT be zero, you will get this:
![\displaystyle x^2 - 7x \\ x[x - 7] = 0; 7, 0 = x \\ \\ Set-Builder\:Notation: [x|7, 0 ≠ x] \\ Interval\:Notation: (-∞, 0) ∪ (0, 7) ∪ (7, ∞)](https://tex.z-dn.net/?f=%5Cdisplaystyle%20x%5E2%20-%207x%20%5C%5C%20x%5Bx%20-%207%5D%20%3D%200%3B%207%2C%200%20%3D%20x%20%5C%5C%20%5C%5C%20Set-Builder%5C%3ANotation%3A%20%5Bx%7C7%2C%200%20%E2%89%A0%20x%5D%20%5C%5C%20Interval%5C%3ANotation%3A%20%28-%E2%88%9E%2C%200%29%20%E2%88%AA%20%280%2C%207%29%20%E2%88%AA%20%287%2C%20%E2%88%9E%29)
I am joyous to assist you anytime.