-2(-5x+9)-9x
-2(-5x)+-2(9)-9x
10x-18-9x
+9 +9
19x=-18
---- ----
19 19
x=-1.05
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
For this case we represent in the complex plane numbers of the form:
a + bi
Where,
a: real part
bi: imaginary part
We represent the real part on the x axis.
We represent the imaginary part in the y axis.
Therefore, for the following numbers we have:
-3 + 8i: quadrant 2
4i: on the vertical axis
6: on the horizontal axis
5-2i: quadrant 4
