<span>For a parallelogram to be proven to be a rectange, the opposide sides must be parallel and the two adjacent sides must be perpendicular.
For two parallel sides, the slope of the two sides is equal.
Thus, for the parallelogram to be a rectangle, AB is parallel to CD.
The slope of AB = (y2 - y1)/(x2 - x1) while the slope of CD = (y4 - y3)/(x4 - x3)
Also, BC is perpedicular to CD.
For two perpendicular sides, the product of the slopes is -1.
The slope of BC is given by (y3 - y2)/(x3 - x2).
Therefore, for the parallelogram to be a rectangle.
(y2 - y1)/(x2 - x1) = (y4 - y3)/(x4 - x3) and (y4 - y3)/(x4 - x3) x (y3 - y2)/(x3 - x2) = -1.
The third option is the correct answer.</span>
Answer:
a. a = 1, b = -5, c = -14
b. a = 1, b = -6, c = 9
c. a = -1, b = -1, c = -3
d. a = 1, b = 0, c = -1
e. a = 1, b = 0, c = -3
Step-by-step explanation:
a. x-ints at 7 and -2
this means that our quadratic equation must factor to:
FOIL:
Simplify:
a = 1, b = -5, c = -14
b. one x-int at 3
this means that the equation will factor to:
FOIL:
Simplify:
a = 1, b = -6, c = 9
c. no x-int and negative y must be less than 0
This means that our vertex must be below the x-axis and our parabola must point down
There are many equations for this, but one could be:
a = -1, b = -1, c = -3
d. one positive x-int, one negative x-int
We can use any x-intercepts, so let's just use -1 and 1
The equation will factor to:
This is a perfect square
FOIL:
a = 1, b = 0, c = -1
e. x-int at 
our equation will factor to:
This is also a perfect square
FOIL and you will get:
a = 1, b = 0, c = -3
Answer:
- boat: 6 mph
- current: 2 mph
Step-by-step explanation:
The relationship between time, speed, and distance is ...
speed = distance/time
For boat speed b and current speed c, the speed downstream is ...
b +c = (16 mi)/(2 h) = 8 mi/h
The speed upstream is ...
b -c = (16 mi)/(4 h) = 4 mi/h
Adding the two equations eliminates the c term:
2b = 12 mi/h
b = 6 mi/h . . . . . divide by 2
Solving the second equation for c, we get ...
c = b -4 mi/h = 6 mi/h -4 mi/h = 2 mi/h
The speed of the boat in still water is 6 mi/h; the current is 2 mi/h.
Answer:
-20f+32
Step-by-step explanation:
-5×4=-20 put the x back
4×8=32
D = k + 20
j = 3k - 120
d = j
k + 20 = 3k - 120
20 + 120 = 3k - k
140 = 2k
140/2 = k
70 = k.....so Katie weighs 70 lbs
David and Johnathan each weigh 90 lbs
