How do you solve 6r+7=13+7r?

2 Answers
Jul 30, 2016

Isolate r on one side of the equation.

Explanation:

In order to do this, let's subtract 7 from each side:

6r=6+7r

Next, let's subtract 7r from each side:

-r=6

Finally, let's divide each side by -1 to get our answer:

r=-6

Jul 30, 2016

r=-6

Explanation:

color(blue)("Method")

Collect the constants on one side of the = and the variables (terms with r ) on the other side. Then manipulate so that you only have a single r on its own on one side and everything else on the other.

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
color(blue)("Applying the method")

color(brown)("Not using short cuts so that you can see where the shortcuts come")color(brown)("from.")

Subtract color(blue)(6r) from both sides

color(brown)(6rcolor(blue)(-6r)+7" "=" "13+7rcolor(blue)(-6r))

" "0+7" "=" "13+r

Subtract color(blue)(13) from both sides

color(brown)(7color(blue)(-13)" "=" "13color(blue)(-13)+r

" "-6" "=" "0+r

r=-6

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The short cut approach for add or subtract is: Move something to the other side of the = and change its sign.