Step-by-step explanation:
1.Given .
2.Being vertically opposite angle.
3.Because sum of all interior angle of a triangle is always 180°.
4.From the statement of 3 number.
5.Because angle 4 = angle 3 and angle 6= angle 1 .
6.(suppose ,< is angle sign) solving this equation,
m<1 + m<2+ m<3 = m<3 + m<5 + m<1
The coordinates of vertex B' is 
.
<h3>
How to calculate the coordinate of point by reflection</h3>
A point if reflected across the line 
by means of the following formula:
![P'(x,y) = P(x,y)+2\cdot [(x_{P}, -2)-P(x,y)]](https://tex.z-dn.net/?f=P%27%28x%2Cy%29%20%3D%20P%28x%2Cy%29%2B2%5Ccdot%20%5B%28x_%7BP%7D%2C%20-2%29-P%28x%2Cy%29%5D)
(1)
Where:
- Original point
- x-Coordinate of point P
- Resulting point
If we know that 
and 
, then the coordinates of the vertex is:
![P'(x,y) = (-2, 4) + 2\cdot [(-2,-2)-(-2,4)]](https://tex.z-dn.net/?f=P%27%28x%2Cy%29%20%3D%20%28-2%2C%204%29%20%2B%202%5Ccdot%20%5B%28-2%2C-2%29-%28-2%2C4%29%5D)
The coordinates of vertex B' is . 
To learn more on reflections, we kindly invite to check this verified question: brainly.com/question/1878272
Answer:
B 9, -9
Step-by-step explanation:
x^2 - 81 = 0
Add 81 to each side
x^2 = 81
Take the square root of each side
sqrt(x^2) = sqrt(81)
x = ±9
Answer:
7.5
Step-by-step explanation:
5/6=x/9
cross multiply
6x=45
x=45/6
x=7 3/6 = 7 1/2 = 7.5
The answer is 96 min, here is why:
x / 240 + x / 160 = 1
<span>2x + 3x = 480 </span>
<span>5x = 480 </span>
<span>x = 96 min
(</span><span>Drainage rate of first pipe = 480000/240 = 2000 l/min </span>
<span>Drainage rate of second tube = 480000/160 = 3000 l/min </span>
<span>Combined drainage rate = 5000 l/min </span>
<span>Time to drain = 480000/5000 = 96 min. )</span>
