So, the distance between two points (x1,y1) and (x2,y2) is:
d = sqrt( (x2-x1)^2 + (y2-y)^2 )
Some times is better the square of the distance:
d^2 = (x2-x1)^2 + (y2-y)^2
Now, in your case:
5^2 = (0-2)^2 + ( -6-k)^2 = (-2)^2 + (6+k)^2 = 4 + (6+k)^2
Notice the little thing about (-6-k)^2 = (6+k)^2 (less '-') Finally:
25 = 4 + (6+k)^2 ===> (6+k)^2 = 21,
6+k = sqrt(21)
Notice we did not expand (6+k)^2! No need this time. But now, the tricky part!
6+k=+sqrt(21) and 6+k=-sqrt(21), because both work (never forget that sqrt come with +/- when looking for solutions!)
k = -6 + sqrt(21) and k=-6-sqrt(21).
Both are valid answers. Some times one is not good because you need the solution be positive (for instance), but here, both are good.
Answer:
D
Step-by-step explanation:
∠ PAR is an angle at the centre of the circle subtended by the arc PR
The central angle is equal to the arc that subtends it, thus
∠ PAR = arc PH + arc HR = 80° + 45° = 125° → D
Answer:
y=x-3
Step-by-step explanation:
To find slope, use m=y2-y1/x2-x1, using values of x and y from two different points. Once you have found slope, take another point and use the point-slope equation y-y1=m(x-x1) and substitute in slope for m and the point for x1 and y1. Isolate y by subtracting y1 from both sides.
Answer: Think what MINUS 1- which will equal 5
Step-by-step explanation: