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
Answer:
We often use everyday definitions of the word "energy," but which statement
best describes what energy is in science?
A. the ability to carry things a long distance
B. the result of eating a lot of carbohydrates
C. the amount of time something can keep moving without rest
D. the ability to do work or cause change
Step-by-step explanation:
Answer:
6.5
Step-by-step explanation:
7 5/8 + 5 3/8= 13
13/2=6.5
Answer:
b) 7.89*10^4
c) 3.15*10^3
Step-by-step explanation:
2-42)
the coefficient in scientific notation (the number that is not 10^x) has to be greater or equal to 1 and less than 10. so c and b are incorrect.
b) 0.789*10^5
c) 31.5*10^2
b) 0.789*10^5
in order to make 0.789 greater than 1, I would just multiply it by 10. shown below
=0.789*10*10*10*10*10
=7.89*10*10*10*10
=7.89*10^4
c) 31.5*10^2
same concept but this time divide by 10 to make 3.15 which will add another *10 to the exponent
=31.5*10*10
=3.15*10*10*10
=3.15*10^3
