Question

Solve the proportion x over x - 4 = 4 over x - 4. What is the value of x?

Answer 1

\(\Large \color{purple}{\rightarrow {x \over x-4} = {4 \over x-4} }\)

Correct?

Answer 2

\(\Large \color{purple}{\rightarrow x(x - 4) = 4(x-4) }\)

We cross-multiply when we have to solve a proportion.

Answer 3

Yes that's correct. How do you solve for x?

Answer 4

\(\Large \color{purple}{\rightarrow x^2 - 4x = 4x - 16 }\)
\(\Large \color{purple}{\rightarrow x^2 =8x - 16}\)
\(\Large \color{purple}{\rightarrow x^2 - 8x = -16 }\)
\(\Large \color{purple}{\rightarrow x^2 - 8x + 16 = 0 }\)

Do you know how to solve a quadratic equation?

Answer 5

This is a proportion. I'l give you my choices.
1. x = 2
2. x = -2 and x = 1
3. x = -1 and x = 4
4. x = 4

Answer 6

Okay,
\(\Large \color{purple}{\rightarrow x^2 - 4x - 4x + 16 = 0 }\)
\(\Large \color{purple}{\rightarrow x(x - 4) - 4(x - 4) }\)
\(\Large \color{purple}{\rightarrow (x - 4)^2 = 0 }\)
\(\Large \color{purple}{\rightarrow x - 4 = 0 }\)
\(\Large \color{purple}{\rightarrow x = 4 }\)

4th option :D

Answer 7

Thanks you so much! :) Do you think you could help me with one more?

Answer 8

I can!

Answer 9

Okay. :)

Answer 10

A map has a scale of 2 km to 3 inches. Which ratio of measures forms a proportion with the map’s scale of km to inches?

Answer 11

DO you want me to give you my choices?

Answer 12

Yes, you have to! It's a proportion.

Answer 13

1. 12 over 18
2. 12 over 24
3. 12 over 14
4. 34 over 36

Answer 14

So, basically, the answer has to be
\(\Large \color{purple}{\rightarrow {2x \over 3x} }\)

Answer 15

12 over 18...?

Answer 16

I find the first correct, because you take x as 6, and you get:
\(\Large \color{purple}{\rightarrow {2*6 \over 3*6} = {12 \over 18} }\)

YESSS!!

Answer 17

Yay! :D I understand! :) Thanks so much!