Answer:
11. 78
12. 4x² - 3x - 1
Step-by-step explanation:
11. Sum of n whole numbers = ½(n² + n)
Multiply
½*n² + ½*n
= n²/2 + n/2
To find the sum of the first 12 whole number, substitute 12 for n into the equation.
= 12²/2 + 12/2
= 144/2 + 12/2
= 72 + 6
= 78
12. Area of trapezoid = ½(a + b)*h
Where,
a = 5x - 4
b = 3x + 2
h = x + 1
Area = ½(5x - 4 + 3x + 2)*(x + 1)
Area = ½(8x - 2)*(x + 1)
Area = ½[8x(x + 1) -2(x + 1)]
= ½[8x² + 8x - 2x - 2]
Add like terms
= ½(8x² - 6x - 2)
= ½(8x²) - ½(6x) - ½(2)
= 4x² - 3x - 1
There are 8 ounces in a cup, so there are 125 cups in 1000 ounces.
1000 / 8 = 125
there are 60 minutes in an hour and 120 minutes in 2 hours
so 1000 ounces / 2 hours is
125 cups / 120 minutes
125 / 120 = 1.04 cups per minute
Check your work
multiply times 60 to get cups per hour
1.04 * 60 = 62.4 cups per hour
multiply times 8 to get ounces per hour
62.4 * 8 = 499.2
multiply times 2 to get ounces per 2 hours
499.2 * 2 = 998.4
the number is not quite 1000 due to rounding the 125 / 120 as it is closer to 1.041666666666667
Step-by-step explanation:
I hope I'm correct. I've never learnt differentiation for log and exponents before
Answer:
x = 17.5
y = 5
Step-by-step explanation:
Similar means that corresponding angles (same colors in this case) are the same. Rotate the 2nd figure on the right in your mind until the angle label colors fit the 1st figure, just so you can tell what's what. Then you can create ratios with corresponding sides that include only one of the unknowns. So 1st we use
x/7 = 15/6
x = 15/6 * 7
x = 17.5
and
y/12.5 = 6/15
y = 6/15 * 12.5
y = 5
