Answer:
7 * 3
7+7+7
3+3+3+3+3+3+3
2+2+2+2+2+2+2+2+2+2+1
(2*10)+1
(10*1)+11....
...and so on
Step-by-step explanation:
I don't know what type of expression you are looking for
It would be O 945 that is the answer
Answer:
-13
Step-by-step explanation:
(7−15−3+5−7)⋅1
Subtract 15 from 7 to get −8.
(−8−3+5−7)×1
Subtract 3 from −8 to get −11.
(−11+5−7)×1
Add −11 and 5 to get −6.
(−6−7)×1
Subtract 7 from −6 to get −13.
−13
Solving a system of equations we will see that we need to use <u>40 liters of the 80% acid solution</u>, and the other <u>20 liters are of the 35% acid solution</u>.
<h3>
How many liters of each solution do we need to use?</h3>
First, we need to define the variables:
- x = liters of the 35% acid used.
- y = liters of the 80% acid used.
We know that we want to produce 60 liters of 65% acid, then we have the system of equations:
x + y = 60
x*0.35 + y*0.80 = 60*0.65
(in the second equation we wrote the percentages in decimal form).
To solve this we need to isolate one of the variables in one equation and then replace it in other one, isolating x we get:
x = 60 - y
Replacing that in the other equation:
(60 - y)*0.35 + y*0.80 = 60*0.65
y*(0.80 - 0.35) = 60*(0.65 - 0.35)
y*0.45 = 60*0.30
y = 60*0.30/0.45 = 40
So we need to use <u>40 liters of the 80% acid solution</u>, and the other <u>20 liters are of the 35% acid solution</u>.
If you want to learn more about systems of equations:
brainly.com/question/13729904
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