Answer:
36
Step-by-step explanation:
Here is the correct and complete question: The units digit of a two-digit number is twice the tens digit. If the digits are reversed, the new number is 9 less than twice the original number. What is the original number?
Lets assume the original number be"10y+x". (x is unit digit and y is 10th digit)
∴ if number is reversed then resulting number be "10x+y".
As given: x= 2y
and 
Now, solving the equation to get original number.

Distributing 2 to 10y and x, then opening the parenthesis.
⇒ 
subtracting by (2x+y) on both side.
⇒ 
subtituting the value of "x", which is equal to 2y.
∴ 
⇒ 
subtracting both side by (16y-9)
⇒ 
cross multiplying
We get, 
y=3
∵x= 2y

∴ x= 6
Therefore, the original number will be 36 as x is the unit number and y as tenth number.
Answer:
B
Step-by-step explanation:
y = 6x + 3 Step-by-step explanation:Givenx = {5, 6, 7, 8, 9}
Answer:
-2480
Step-by-step explanation:
31 * -80 =-2480
Not sure how to explain this more, but I hope this helps!
Answer is in the photo. I can't attach it here, but I uploaded it to a file hosting. link below! Good Luck!
tinyurl.com/wpazsebu
Answer:
Step-by-step explanation:
90x - 60y = 68.....multiply by -1
90x - 70y = 91
---------------------------
-90x + 60y = -68 (result of multiplying by -1)
90x - 70y = 91
---------------------------add
-10y = 23
y = -23/10 <===
90x - 60y = 68
90x - 60(-23/10) = 68
90x + 138 = 68
90x = 68 - 138
90x = - 70
x = -70/90
x = -7/9 <=====