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
Answer:
The area is 45 units squared
Step-by-step explanation:
If the rectangle's width is 3 units, and the length is 5 times then:
5 x 3 = 15
So the length is 15 units
The area is length times width
15 x 3 = 45
The area is 45 units squared
Answer:
a) x=60°, 2x=120°
b) x=36°
Step-by-step explanation:
To convert this equation into slope intercept form simply distribute the number of -2 and put it in
Y = mx + b form
Y + 4 = -2(X-1)
Y + 4 = -2x + 2
Y = -2X + 2 - 4
Y = -2X - 2
I believe this is the solution in slope intercept form.
Answer:
x=9
Step-by-step explanation:
The expression is for the interior angle of the hexagon; one interior angle is equal to .
Since an interior angle of a hexagon measures 120°, we have the equality
.
Now it is just a matter of solving for
11x=120-21
11x=99
x=99/11
x=9
