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%.
Answer:
BC:BN=8:3
Step-by-step explanation:
ABCD is a trapezoid and there is a point m which belongs to AD such that AM:MD=3:5.Line "l" parallel to AB intersects the diagonal AC at p and BD at N.
Now, we know that the parallel lines divide the transversal into the segments with equal ratio, therefore, BN:NC=AM:MD
But, BC= BN+NC
Therefore, BC:BN=(BN+NC):BN
⇒BC:BN=(3+5):3
⇒BC:BN=8:3
Answer : y>0
f(x) = 9*2^x
f(x) is an exponential function

When we plug in positive value for x , the value of y is positive
When we plug in negative value for x , the value y is also positive
So for any value of x, the y value is positive always.
Range is the set of y values for which the function is defined
y values are positive , so range is y >0
Answer:


<em>f(x) and g(x) and not inverse functions</em>
Step-by-step explanation:
Given


Required
Determine f(g(x))
Determine g(f(x))
Determine if both functions are inverse:
Calculating f(g(x))



Expand Brackets




Calculating g(f(x))




Expand Brackets



Checking for inverse functions

Represent f(x) with y

Swap positions of x and y

Subtract 9 from both sides



Divide through by 3


Take square root of both sides


Represent y with g(x)

Note that the resulting value of g(x) is not the same as 
<em>Hence, f(x) and g(x) and not inverse functions</em>
Answer:
Step-by-step explanation:
The distance the light traveled to the ground is the range of the plane expressed as:
R = U*√2H/g
U is he velocity
H is the max height
g is the acc. due to gravity
Let us get U first using the formula
H = u²sin²Ф/2g
1000 = u²sin²60/2(9.81)
1000*19.62 = 0.8660u²
19620 = 0.8660u²
u² = 19620/0.8660
u² = 22655.88
u = √22655.88
u = 150.52m/s
Next is to get the range
R = 150.52√2(1000)/9.81
R = 150.52 √2000/9.81
R = 150.52√203.87
R = 150.52*14.28
R = 2149.16m
Hence the distance the light traveled to the ground is 2,149.16m