They multiplied 7/19 with - 70. If we write this as a fraction it looks like this:
[tex] \frac{7}{19} \times ( - \frac{70}{1} )[/tex]
When you multiply these fractions you get this:
[tex] \frac{7}{19} \times ( - \frac{70}{1} ) = - \frac{490}{19} \\ - \frac{490}{19} = - 25 \frac{15}{19} [/tex]
You get 25 15/19 because you divide 490 by 19.
Next what you want to do is put 9 onto the right side of the equasion. So now you have:
[tex]y - 9 = \frac{7}{19}x - 25 \frac{15}{19} [/tex]
And you put 9 onto the right side of the equasion...
[tex]y = \frac{7}{19} x - 25 \frac{15}{19} + 9[/tex]
Now we can see that we can add 9 to -25 15/19
[tex] - 25 \frac{15}{19} + 9[/tex]
We need a common denominator to solve this, which in this case is 19. It goes as follows:
[tex] - 25 \frac{15}{19} + \frac{9}{1} = \\ - 25 \frac{15}{19} + \frac{171}{19} = \\ - \frac{490}{19} + \frac{171}{19} = \\ - \frac{319}{19} = \\ - 16 \frac{15}{19} [/tex]
See that we changed -25 15/19 back into 490/19 to solve the equasion easier. The result is -16 15/19 which is approximately -16.8 in decimal form.
I hope I explained it well!
