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
11 miles / 20 miles =.55
.55 x 100 = 55%
11/20 is the proportion and you multiply by 100 to gey a percent
another way to solve is
11/20 x 5/5 = 55/100 = 55%
you multiply by 5/5 because it is equal to one and it makes the denominator equal to 100 it also follows the rule that whatever you do to the top you must do with the bottom
Answer:
y = 5x + 8
Explanation:
The slope is 5, and the y intercept is 8 so following the format of the equation, the equation for this line is:
y = 5x + 8
To answer this go to the guys link on top
Answer: 45
Step-by-step explanation:
The total degrees in a circle is 360.
The perpendicular angle that you see is 90 degrees, added to angles of x and 3x, you get the total degrees.
so 90 + x + 3x = 90 + 4x = total
90 + 4x = 360
4x = 180
x = 45 degrees
