In a two-digit number, the units digit is twice the tens digit. If the number is doubled it will be 9 more than the number reversed. Find the number.

T=Tens

U=Unit

From the question... The Unit digit is twice the Tens digit

Let the Number be xy

Meaning

y is the unit number

x is the tenth Number

Can be inferred for the question that

y=2x (i)

Also

If the Number is doubled x2(times 2)

"It'll be 9more than the reversed"

Now listen

if you want to express a 2digit Number...

Let's say 45...

It can be expressed as 10x4 + 5 = 45

or

66 can be expressed as 10x6 + 6 = 66

So

It'd be better if we express this our unknown number like that too

So

Let's express "xy" like "10x + y"

Hope you grab?

Now from the second statement of the question..

If The Number is doubled...It'll be 9 more than the reversed

What is the reverse of that Number??

The reverse would be "10y + x"

You can see that x and y switched places.

so

The statement said...

2(10x + y) + 9 = 10y + x (reversed)

20x + 2y + 9 =10y + x (ii)

Recall from our first eqn

y=2x

Now substitute y=2x into eqn ii

20x + 2(2x) + 9 = 10(2x) + x

20x + 4x +9 = 20x + x

20x - 20x + 4x - x = -9

3x = -9

x=-3

y=2x

y=2(-3)

y=-6

So The Number is 10x + y

= 10(-3) + (-6)

=-30-6

=-36

This answer obeyed the first part of the question because the unit is twice digit(2x3)

Let's check if it obeyed the second part

2[(10(-3) + (-6)] + 9 = 10(-6) + (-3)

2(-30-6) + 9 = -60-3

-63=-63

The 2nd part is also true.

So

Our Number is -36.

I'm Open to corrections if you spot any.

the system of inequity is

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

the solid line passing through the points (0,4) and (4,0).

the related equation of solid line is .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

the related equation of dashed line is

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be . the required inequality is

similarly, check the second related equation.

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is