Answer:
15.

16. 10 ml of 20% saline and 40 ml of 10% saline
Step-by-step explanation:
A chemist takes x ml of 20% saline and y ml of 10% saline. In total, he takes
x + y ml that is 50 ml, so

There are
ml of salt in x ml of 20% saline and
ml of salt in 10% saline. There are
ml of salt in 50 ml of 12% saline. Thus,

15. We get the system of two equations:

16. Solve this system. From the first equation:

Substitute it into the second equation:

Answer:
58
Step-by-step explanation:
Answer:
see explanation
Step-by-step explanation:
x = r cosΘ
y = r sinΘ
with r = 54 and Θ = 69°, thus
x = 54cos69° ≈ 19.4
y = 54sin69° ≈ 50.4
Thus (54, 69° ) as an ordered pair
= ![\left[\begin{array}{ccc}19.4\\50.4\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D19.4%5C%5C50.4%5C%5C%5Cend%7Barray%7D%5Cright%5D)
Answer:
B. the second one
Step-by-step explanation:
Hello,
x² + 5x + 6 = 0
a = 1 ; b = 5 ; c = 6
∆ = b² - 4ac = 5² - 4 × 1 × 6 = 25 - 24 = 1 > 0
2 solutions :


S = { -3 ; -2}