zainabmustapha0 zainabmustapha0

25-10-2014
Mathematics

Answered

A number is such that its ten digit is twice its unit digit. Prove that the number itself must be seven times the sum of its digit

Answer :

konrad509 konrad509

25-10-2014

x - ten digit
y - unit digit

[tex]x=2y\\ 10x+y=7(x+y)\\\\ 10\cdot2y+y=7(2y+y)\\ 20y+y=14y+7y\\ 21y=21y \Rightarrow y\in \mathb{R}\Rightarrow x\in \mathb{R}[/tex]

So it's true.

Answer Link

Other Questions

What happens when there exists lactose in the transcriptional mechanism?

Select the correct text in the passage.The excerpt is taken from Patrick Henry's famous "Give me liberty or give me death" speech at the Second Virginia Convent

how do you solve for b b=360x5/18

illegal polluting/dumping of hazardous chemicals

What is the h c f of 200 and 240

Statistical sensitivity is the probability of having a positive test if the person has the illness. True False

Patient A has a mutation that negatively impacts the function of the p53 transcription factor. Cells in Patient A will:A. Enter into a modified G₁ phase called

Suppose there are two functions [tex]f[/tex] and [tex]g[/tex], whose values are defined by the table below. Calculate [tex]f^{-1}(g(2))[/tex].\begin{tabular}{|l

Which one of the following is/are true concerning the US Federal Reserve during the pandemic?(I) It made made forgivable loans to foreign central banks(II) It w

Use your calculator to work out the value of[tex]\[ \frac{\sqrt{41.5 + 0.59}}{4.95} \][/tex]Write down all the digits you see on your calculator display.

What latitudes are most likely to see glaciers

why does sodium hydroxide solution affect the requirements for photosynthesis?

this is stumping me. it's a geometry proof question, and i really need help! diagram and statements are attached in a picture.

Examples of irony in true grit

You have to use the numbers 1,2,3,4 and 5. Add those numbers and the sum should be equal to 50. You can combine the numbers to form tens (i.e 2 and 4 is 24) but

Soil liquefaction occurs when

mountains that form when large areas of earth gradually move skyward as a unit are called

identify the belief system that spread to China from India during the late Han period and appealed to the people during the trubuleng times

Which of the following linear equations, when graphed on a coordinate grid has the steepest slope?A: y = 1/3x – 2 B: y = 5/2x – 1 C: y = 3x + 1/4D: y = 4x +

if 5 slices of pizza cost $5:50 how much does -two slices cost-ten slices cost-and half a slice