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
1. (1.35)x(.42)
1.35
x. .42
________
270
5400
________
.5670
You need to have the total number of decimal places from the original two numbers. 1.35 has two decimal places and .42 has to decimal places you have a total of four decimal places, Which means 5670 is .5670
2. (.22)x(.04)
.22
x. .04
_______
88
00
_______
.0088
you need to have the total number of decimal places from the original Two numbers. So .22 is two decimal places and .04 is two decimal places, so you will need to have for decimal places. That means that the answer 88 needs to be translated into .0088
Answer:
C complex
Step-by-step explanation:
a+ bi
a is the real part and bi is the imaginary part
Together they make a complex number
When solving a system of equations by graphing it, and there is no intersection between the lines, then it has no solutions.
