The digit at ones place of a two digit number is three times the digit at tens place. When 54 is added to the number its digit are reversed. Find the number

The number is 39

Step-by-step explanation:

Let the number at the tens place be x and the number at ones place be y.

Hence, The number is 10x + y.

From the question, the digit at ones place (y) is three times the digit at tens place (x). That is, y is three times x. This means

y = 3x (1)

Also, When 54 is added to the number, its digits are reversed (That is, the resulting number would be 10y + x). This means

10x + y + 54 = 10y + x (2)

Put the value of y = 3x from equation (1) into equation (2) to solve for x

Then,

10x + y + 54 = 10y + x

10x + 3x + 54 = 10(3x) + x

13x + 54 = 30x + x

13x + 54 = 31x

31x - 13x = 54

18x = 54

x = 54/18

x = 3.

Now, Put the value of x = 3 into equation (1) to solve for y

y = 3x

y = 3(3)

y = 9.

Hence, x = 3 and y = 9.

Since the number is 10x + y

Substitute the values of x and y.

Then,

10x + y = 10(3) + 9

=30 + 9

= 39

Hence, the number is 39.

a.

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1