Giving away indicates subtraction. Therefore, the expression is 45 - b.
Answer:
45
Step-by-step explanation:
A number consists of 2 digits whose sum is 9 => x + y = 9
If the order of the numbers is inverted, the result is equal to the given number plus 9 units => (10*y + x) + 9 = (10*x + y)
Thus:
x + y = 9 => multiply by -9 => 9*y + 9*x = 81
10*y + x + 9 = 10*x + y => 9*y - 9*x = -9
We are left then that:
9*y + 9*x = 81 (1)
9*y - 9*x = -9 (2)
we add both equations
18y = 72
y = 72/18 = 4
replacing
x + y = 9
x + 4 = 9
x = 5
Therefore the number is (10y + x) => (10 * 4 + 5) => 45
To multiply a number, simply take a number (Let's say 4) and another number (Let's say 3). If you multiply 4 by 3, you are simply taking the number 4, and adding it to itself 3 times (4 + 4 + 4).
I hope this makes sense, please tell me if you need some more information.
Hope this helps!
Answer:
Step-by-step explanation:
Simple interest = 
End of first year = 650+19.5 = $669.50
End of second year = 669.50+19.5 = $ 689
End of third year = 689+19.5 = $708.50
End of fourth year = 708.50 +19.5 = $ 728
End of fifth year = 728 +19.5 = $747.50
