If x and y in the equations

1 answer:

5 0

We can let
a = 1/(x-1)
b = 1/(y+2)
and rewrite the equations as
2a - b = 10
a + 3b = -9
Using the first to write an expression for b, we get
b = 2a - 10
Substituting this into the second equation gives
a + 3(2a -10) = -9
7a -30 = -9 . . . . . . . . simplify
7a = 21 . . . . . . . . . . .add 30
a = 3
b = 2·3 - 10 = -4

Now, we can find x and y.
   3 = 1/(x -1)
   x - 1 = 1/3
   x = 1 1/3 = 4/3

  -4 = 1/(y +2)
  y +2 = -1/4
  y = -2 1/4 = -9/4

Then the desired sum is
  x + y = 4/3 -9/4 = (16 -27)/12
x + y = -11/12

The appropriate choice is ..
c. -11/12

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a circle has a circumstance of 20. it has an arc on length 4. what is the central angle of the arc in degrees?

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Answer:

∠72°.

Step-by-step explanation:

If a circle has a circumference of 20 and an arc with a length of 4, we can simply set up a ratio to determine the angle of the arc in degrees:

$\frac{4}{20} = \frac{x}{360}$