Answer:
C
Step-by-step explanation:
Since y will have same value, y doesn't really matter. Thus,
We can solve for y in the 2nd equation as:
-3x - y = 4
-3x - 4 = y
Now we can plug it into the first and solve for x:
-9x + 4y = 8
-9x + 4(-3x - 4) = 8
-9x - 12x - 16 = 8
-21x = 8 + 16
-21x = 24
x = 24/-21
x = -8/7
Correct answer is C.
Answer:
a) x₁ = 14
x₂ = - 6
b) x = 4
c) P(max ) = 4000000 $
Step-by-step explanation:
To find the axis of symmetry we solve the equation
a) -4x² + 32x + 336 = 0
4x² - 32x - 336 = 0 or x² - 8x - 84 = 0
x₁,₂ = [ -b ± √b² -4ac ]/2a
x₁,₂ = [ 8 ±√(64) + 336 ]/2
x₁,₂ = [ 8 ± √400 ]/2
x₁,₂ =( 8 ± 20 )/2
x₁ = 14
x₂ = -6
a) Axis of symmetry must go through the middle point between the roots
x = 4 is the axis of symmetry
c) P = -4x² + 32x + 336
Taking derivatives on both sides of the equation we get
P´(x) = - 8x + 32 ⇒ P´(x) = 0 - 8x + 32
x = 32/8
x = 4 Company has to sell 4 ( 4000 snowboard)
to get a profit :
P = - 4*(4)² + 32*(4) + 336
P(max) = -64 + 128 + 336
P(max) = 400 or 400* 10000 = 4000000
Answer:
56.25 pound of the coffee that costs $5 per pound is needed
18.75 pound of the coffee that costs $9 per pound is needed
Step-by-step explanation:
Let the number of pounds be x and y respectively
The total pounds is 75;
So;
x + y. = 75 •••••••(i)
Total cost of first type
9 * x = $9x
Total cost of second type;
5 * y= $5y
75 pound at $6 per pound; total cost of this is;
6 * 75 = $450
Thus;
9x + 5y = 450 ••••••••(ii)
From i, x = 75-y
Put this into ii
9(75-y) + 5y = 450
675 -9y + 5y = 450
4y = 675-450
4y = 225
y = 225/4
y = 56.25
x = 75 - y from i
x = 75-56.25
x = $18.75
there are 4 Aces and 4 8's for a total of 8 cards
52 cards in a deck
so probability of picking an Ace or 8 = 8/52
