## How-to-solve-solution-sets

From Omilili

### How do you guys set Ph/EC of solutions?

The pH up or down with nitric acid/phosphoric acid or potassium hidroxide. What I realize is when I m going to check the final EC of my solutions before watering, my EC get too high with the acids should both be 0.0ec... where are you guys getting distilled that has shit in it? By definition

Question:Employees of a discount appliance store receive an additional 20% off of the lowest price on an item. If an employee purchases a dishwasher during a 15% off sale, how much will he pay if the dishwasher originally cost \$450?

Answers:I believe I need to have 1 more question to answer, as the additional discount can be added with the 15% off on the lowest price, or the additional discount is applied after the 15% is off from the lowest price. I'll illustrate how the 2 methods of calculation will come up with 2 different net prices. 1) discount rate: 15%+20%=35% off. 450 - (450x35%) = 450 - 157.5 = 292.5 (net price) 2) discount rate: first 15%, then 20% 450 - (450x15%) = 450 - 67.5 = 382.5 382.5 - (382.5x20%) = 382.5 - 76.5 = 306 (net price)

Question:solve with addition 2x+1 is less than or equal to x+13 and 19-8y-5y<58

Answers:2x+1 <= x+13 step 1: subtract 1 from both sides and get 2x <= x +12 step 2: subtract x from both sides and get x <= 12 ( x is less than or equal to twelve ------------------------------------------------------------------------------ 19 - 8y - 5y < 58 step 1: collect y terms and get 19 - 13y < 58 step 2: subtract 19 from both sides and get -13y < 39 step 3: divide both sides by -13 and get y > -3 (answer) note: the reason why the < turned into a > is because you divided by a negative number. you switch that logic sign whenever dividing by a negative.

Question:Media Services charges \$30 for a phone and \$20/month for it s economy plan. The equation c = 20t 30 describes the total cost, c, of operating a Media Services phone for t months. The total cost for 7 months of service is \$__ If a customer has only \$80 available, how many months of service can she receive? A.2 1/3 B.2 C.3 D.2 Choose the correct graph of the equation c = 20t 30. Solve for the indicated letter. C = 2d, for d The solution is d = __

Answers:Plug it in: cost = 20(7) + 30 = \$170 for the next one solve backwards: 80 = 20T + 30 subtract 30 50 = 20T divide by 20 d = 2.5 so the answer looks like choice D but can you buy half a month? Usually these answers must be a whole number so choice B You never showed the graph but it is the one that passes through 30 on the vertical axis and passes through the points (1,50); (2,70);(3,90)... C = 2d divide by 2 to get d =C/2