Question

Teaching my little sister math and not sure myself on this question that she asked: Why didn't the 10 stay negative in the equation, why does it have to go to the 4x?

Answer 1

@Vocaloid
@dude

Answer 2

ok, assuming she understands up to this part;

5y = 4x - 10

in standard form, everything gets "moved" to one side of the equal sign

in order to do this, we have to both: subtract 4x from both sides, and add 10 to both sides

therefore, the -10 cancels out on the right side, and you're left with +10 on the left side

Answer 3

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
ok, assuming she understands up to this part;

5y = 4x - 10

in standard form, everything gets "moved" to one side of the equal sign

in order to do this, we have to both: subtract 4x from both sides, and add 10 to both sides

therefore, the -10 cancels out on the right side, and you're left with +10 on the left side
\(\color{#0cbb34}{\text{End of Quote}}\)
yes, but couldnt you just subtract the 5y from both sides and the 10 will remain negative?

Answer 4

yes, if they subtracted 5y from both sides they'd end up with
4x + 5y + 10 = 0

however, that's not the way they did it in the steps shown

Answer 5

both methods essentially lead to the same result, it's just one equation is the other equation multiplied by (-1)

Answer 6

makes sense, thank you!

Answer 7

They came up with something else, now my little sister is counting the dust bunnies on the floor :S

Answer 8

oof

any way to show us her work?

Answer 9

well this is the lesson... im the one teaching my sister how to do it they justprovide a video

Answer 10

the video is saying this