Question

Solve the equation. 78 = -2(m + 3) + m Question 11 options: –42 –28 –84 –72

Answer 1

Hey there, hope I can help!

First switch the sides

`-2\left(m+3\right)+m=78`


`Expand\;-2\left(m+3\right)+m`


`-2\left(m+3\right)`

`\mathrm{Distribute\:parentheses\:using}: \:a\left(b+c\right)=ab+ac`

`Where\;a=-2,\:b=m,\:c=3`

`-2\cdot \:m-2\cdot \:3`


`\mathrm{Multiply\:the\:numbers:}\:2\cdot \:3=6 \ \textgreater \ -2m-6 \ \textgreater \ -2m-6+m`

Simply group the like terms

`-2m+m-6`

Add the similar elements which is -2m + m > -m > -m - 6 = 78


`\mathrm{Add\:}6\mathrm{\:to\:both\:sides} \ \textgreater \ -m-6+6=78+6`

Simplify
-m = 84


`\mathrm{Divide\:both\:sides\:by\:}-1 \ \textgreater \ (-m)/(-1)=(84)/(-1) \ \textgreater \ Simplify \ \textgreater \ m=-84`

Hope this helps!

Answer 2

Before we begin, note the following:
+ve * +ve = +ve
-ve * -ve = +ve
+ve * -ve = -ve
-ve * +ve = -ve

Now, for the given question:
The given equation is:
78 = -2(m+3) + m

To solve for m, we need to isolate m on one side of the equation and compute its value as follows:
78 = -2(m+3) + m
78 = -2m - 6 + m
m-2m = 78+6
-m = 84
m = 84/-1
m = -84