Answer:
<h2>C.</h2>
Step-by-step explanation:
<, > - open circle
≤, ≥ - solid circle
<, ≤ - draw to the left
>, ≥ - draw to the right

Try, please, this:
1) Imagine, that pharmacist used 'x' gr. of 40% solution and 'y' of 70% solution.
Together (20 gr. of 52% sol.) it will be x+y=20.
2) From other side, the pharmacist combined 40x and 70y gramms, after obtaining together it is 52(x+y) gramms. In other words 40x+70y=52(x+y)
3)

Answer: 8 gr. of 70% solution and 12 gr. of 40%.
We have been given two inequalities
and
. We are asked to find the integers that satisfy both inequalities.
Let us solve for our 1st inequality.




Upon combining our both inequalities, we will get:

This means that solution of our inequalities is x values greater than
and less than
.
We know that integers between
and
are:
.
Therefore, our solution would be
.
Answer:
x=28°
Step-by-step explanation:
supplementary angles equal 180°
So:
3x+2x+x+12=180°
6x+12=180
6x=168
x=28°
Therefore:
3x:
3(28)=84°
2x:
2(28)=26°
x+12:
28+12=40°