There are

ways of selecting two of the six blocks at random. The probability that one of them contains an error is

So

has probability mass function

These are the only two cases since there is only one error known to exist in the code; any two blocks of code chosen at random must either contain the error or not.
The expected value of finding an error is then
Problem:
Solve
2
x
+
5
y
=
−
3
;
3
x
−
y
=
21
Steps:
I will try to solve your system of equations.
3
x
−
y
=
21
;
2
x
+
5
y
=
−
3
Step: Solve
3
x
−
y
=
21
for y:
3
x
−
y
+
−
3
x
=
21
+
−
3
x
(Add -3x to both sides)
−
y
=
−
3
x
+
21
−
y
−
1
=
−
3
x
+
21
−
1
(Divide both sides by -1)
y
=
3
x
−
21
Step: Substitute
3
x
−
21
for
y
in
2
x
+
5
y
=
−
3
:
2
x
+
5
y
=
−
3
2
x
+
5
(
3
x
−
21
)
=
−
3
17
x
−
105
=
−
3
(Simplify both sides of the equation)
17
x
−
105
+
105
=
−
3
+
105
(Add 105 to both sides)
17
x
=
102
17
x
17
=
102
17
(Divide both sides by 17)
x
=
6
Step: Substitute
6
for
x
in
y
=
3
x
−
21
:
y
=
3
x
−
21
y
=
(
3
)
(
6
)
−
21
y
=
−
3
(Simplify both sides of the equation)
Answer:
y
=
−
3
and
x
=
6
Given:
Consider the completer question is "If ∆BTS≅∆GHD, BS=25, TS=14, BT=31, GD=4x-11, m∠S=56, m∠B=21 and m∠H=(7y+5), find the values of x and y.
To find:
The values of x and y.
Solution:
We have,
(Given)
(CPCTC)



Divide both sides by 4.

In ∆BTS,
(Angle sum property)




Now,
(CPCTC)



Divide both sides by 7.

Therefore, the value of x is 9 and value of y is 14.
Answer:
A bit of a doosy, but bare with me: f*g*h(x) = 
Step-by-step explanation:
So explaining this is a bit awkward as well, but I can try...So
Starting from g(x) working that backwards into f(x), so...
g(x) = 
f(x) = 
Take your g(x) and plug it into your f(x) into every x you see
f(g(x)) =
~ I hope you can visualize this, but do you see how g(x) plugs into f(x)...
Now you still have one more step which you still need to include h(x), so
Remember h(x) = 
Now plug in your h(x) into every x you see from f(g(x)) and it should look like...

Bill received $144 more than Pam.
Explanation:
To create the ratio, we can divide 360 by 5 which equals 72.
3x72= 216
360
The ratio that is proportionate to 3:5 is 216:360
So, 360 - 216 = 144