Answer:
A two-digit number can be written as:
a*10 + b*1
Where a and b are single-digit numbers, and a ≠ 0.
We know that:
"The sum of a two-digit number and the number obtained by interchanging the digits is 132."
then:
a*10 + b*1 + (b*10 + a*1) = 132
And we also know that the digits differ by 2.
then:
a = b + 2
or
a = b - 2
So let's solve this:
We start with the equation:
a*10 + b*1 + (b*10 + a*1) = 132
(a*10 + a) + (b*10 + b) = 132
a*11 + b*11 = 132
(a + b)*11 = 132
(a + b) = 132/11 = 12
Then:
a + b = 12
And remember that:
a = b + 2
or
a = b - 2
Then if we select the first one, we get:
a + b = 12
(b + 2) + b = 12
2*b + 2 = 12
2*b = 12 -2 = 10
b = 10/2 = 5
b = 5
then a = b + 2= 5 + 2 = 7
The number is 75.
And if we selected:
a = b - 2, we would get the number 57.
Both are valid solutions because we are changing the order of the digits, so is the same:
75 + 57
than
57 + 75.
These are the two rules for when a and b are positive numbers.
a + b = b + a
a - b ≠ b -a
a - b = -b + a
For example:
5.71 + 2.84 = 2.84 + 5.71
8.55 = 8.55
5.71 - 2.84 ≠ 2.84 - 5.71
2.87 ≠ -2.87
5.71 - 2.84 = -2.84 + 5.71
2.87 = 2.87
These are the rules for when a and b are negative numbers.
a + b = b + a
a - b = b + a
For example,
-6.2 + (-3.96) = -3.96 + (-6.2)
-6.2 - 3.96 = -3.96 - 6.2
-10.16 = -10.16
-6.2 - (3.96) = -3.96 + (-6.2)
-10.16 = -10.16
Also, if a is a positive number, while b is a negative number, we see these rules:
a + b = a - b
a - b = a + b
For example,
5.71 + (-6.2) = 5.71 - 6.2
-0.49 = -0.49
5.71 - (-6.2) = 5.71 + 6.2
11.91 = 11.91
Also, if a is a negative number while b is a positive number, then these rules will apply:
a + b = b - a
a - b = -b - a
For example,
-3.96 + 2.84 = 2.84 - 3.96
-1.12 = <span>-1.12
</span>
-3.96 - 2.84 = -2.84 - 3.96
-6.8 = -6.8
I hope this helps! :)
Answer:
41/10
Explanation:
sqrt16 = 4
sqrt17 = 4.12
4.1 = 41/10 and 4<4.1<4.12
I believe the answer is D
