Hello,
We have : (a + b)² = a² + 2ab + b²
4x² + 20x + 25 = (2x)² + 2 × 2x × 5 + 5² = (2x + 5)² → answer B
Here, we have a = 2x and b = 5 !
Answer:
x = 10 cm, y = 5 cm gives a minimum area of 300 cm^2.
Step-by-step explanation:
V= x^2y = 500
Surface area A = x^2 + 4xy.
From the first equation y = 500/x^2
So substituting for y in the equation for the surface area:
A = x^2 + 4x * 500/x^2
A = x^2 + 2000/x
Finding the derivative:
dA/dx = 2x - 2000x^-2
dA/dx = 2x - 2000/x^2
This = 0 for a minimum/maximum value of A, so
2x - 2000/x^2 = 0
2x^3 - 2000 = 0
x^3 = 2000/ 2 = 1000
x = 10
Second derivative is 2 + 4000/x^3
when x = 10 this is positive so x = 10 gives a minimum value of A.
So y = 500/x^2
= 500/100
= 5.
Answer:
30%
Step-by-step explanation:
there are two numbers that fit in the x<=3 category, those being -3 and -5, so you add the two decimals for them (.17 and .13) to get .30 and move the decimal two times to the right to make it in percentage form.
the numbers are 6 and 13
let x be one of the numbers then the other is 2x + 1
their sum increased by 7 = 26
x + 2x + 1 + 7 = 26
3x + 8 = 26
subtract 8 from both sides
3x = 26 - 8 = 18
divide both sides by 3
x = 
= 6
the numbers are 6 and (2 × 6) + 1 = 12 + 1 = 13
Answer:
a) 103
explanation:
it occurred the most in the stem & leaf plot (3 times)
