Answer: 
Step-by-step explanation:
We have the following function:

And we have to evaluate it when
, this means we have to substitute
by
:

Solving:

Finally:

-7 -14(1/7)
remove parenthesis
14 * 1/7 = 2 (14/1 * 1/7 = 2/1 which we reduce to just 2)
-7 -2
-9
Answer:
Width = 2
Length = 5
Step-by-step explanation:
let A be the area of the rectangle
L be the length of the rectangle
w be the width of the rectangle
<u><em>Formula</em></u>: ‘<u><em>area of a rectangle</em></u>’
A = L × w
…………………………………………………
A = L × w
⇔ 10 = (w + 3) × w
⇔ 10 = w² + 3w
⇔ w² + 3w - 10 = 0
<u><em>Solving the quadratic equation</em></u> w² + 3w - 10 = 0 :
Δ = 3² - 4(1)(-10) = 9 - (-40) = 9 + 40 = 49
then √Δ = 7


-5 is not valid ,because w represents the width
which must be a positive number
Then w = 2
<u><em>Conclusion</em></u>:
Width = 2
Length = 2 + 3 = 5
Answer:
If
is divisible by 3, the n is also divisible by 3.
Step-by-step explanation:
We will prove this with the help of contrapositive that is we prove that if n is not divisible by 3, then,
is not divisible by 3.
Let n not be divisible by 3. Then
can be written in the form of fraction
, where x and y are co-prime to each other or in other words the fraction is in lowest form.
Now, squaring

Thus,


It can be clearly seen that the fraction
is in lowest form.
Hence,
is not divisible by 3.
Thus, by contrapositivity if
is divisible by 3, the n is also divisible by 3.