Answer: The correct answer is: [D]: "8" .
Step-by-step explanation:f y varies inversely with x; then y = k/x ; with "k" being the "constant" in this equation.
You can find the constant by substituting the values given: x = 16, f(x) = y = 2 ;
So, f(x) = y = 2 = k/16 ;
→ 2 = k / 16 ;
Solve for the constant; "k" ;
Multiply EACH SIDE of the equation by "16"
→ 16* (2) = (k / 16) * 16 ;
→ 32 = k ;
↔ k = 32 ;
As such, we can write the equation:
y = k/ x ; as:
→ y = 32/ x ;
Since we are given: "x = 4" ; Plug in that value; and solve for "y" ;
y = 32/4 = 8 .
y = 8 .
y = f(x) ;
So; f(x) = 8 ; which is: Answer choice: [D]: "8" .
Answer:
x = 4; y = 2
Step-by-step explanation:
(1) 3x + 2y = 16
(2) 2x – 2y = 4 Add (1) and (2)
5x = 20 Divide each side by 5
(3) x = 4 Substitute (3) into (2)
2×4 – 2y = 4
8 - 2y = 4 Subtract 16 from each side
-2y = -4 Divide each side by -2
y = 2
<em>Check:
</em>
(1) 3×4 + 2×2 = 16
12 + 4 = 16
16 = 16
(2) 2×4 – 2×2 = 4
8 - 4 = 4
4 = 4
Find the total cost of producing 5 widgets. Widget Wonders produces widgets. They have found that the cost, c(x), of making x widgets is a quadratic function in terms of x. The company also discovered that it costs $15.50 to produce 3 widgets, $23.50 to produce 7 widgets, and $56 to produce 12 widgets.
OK...so we have
a(7)^2 + b(7) + c = 23.50 → 49a + 7b + c = 23.50 (1)
a(3)^2 + b(3) + c = 15.50 → 9a + 3b + c = 15.50 subtracting the second equation from the first, we have
40a + 4b = 8 → 10a + b = 2 (2)
Also
a(12)^2 + b(12) + c = 56 → 144a + 12b + c = 56 and subtracting (1) from this gives us
95a + 5b = 32.50
And using(2) we have
95a + 5b = 32.50 (3)
10a + b = 2.00 multiplying the second equation by -5 and adding this to (3) ,we have
45a = 22.50 divide both sides by 45 and a = 1/2 and using (2) to find b, we have
10(1/2) + b = 2
5 + b = 2 b = -3
And we can use 9a + 3b + c = 15.50 to find "c"
9(1/2) + 3(-3) + c = 15.50
9/2 - 9 + c = 15.50
-4.5 + c = 15.50
c = 20
So our function is
c(x) = (1/2)x^2 - (3)x + 20
And the cost to produce 5 widgets is = $17.50
The solution to this equation is x=4.6 because 19.32/4.2=4.6
