Question

0.4(20 - 10m) = 2.5 - 2m - 12.5 solve for m show your work

Answer 1

m= 9.

Explanation:

1. Write the expression.

`0.4(20 - 10m) = 2.5 - 2m - 12.5`

2. Apply the distributive property of multiplication on the left hand side of the equation.

`(0.4)(20)-(0.4)(10m)= 2.5 - 2m - 12.5\\ \\(8)-(4m)= 2.5 - 2m - 12.5\\ \\8-4m= 2.5 - 2m - 12.5`

3. Subtract 8 from both sides of the equation.

`8-4m-8= 2.5 - 2m - 12.5-8\\ \\-4m=2.5-2m-20.5\\ \\-4m=-2m-18`

4. Add "2m" from both sides.

`-4m+2m=-2m-18+2m\\ \\-2m=-18`

5. Divide both sides by "-2".

`(-2m)/(-2) =(-18)/(-2) \\ \\m=9`

6. Verify the answer by substituting the calculated value of m into the original equation and simplifying.

`0.4(20 - 10(9)) = 2.5 - 2(9) - 12.5\\\\0.4(20 - (90)) = 2.5 - (18) - 12.5\\ \\0.4(-70) = -28\\ \\-28=-28`

That's correct. Therefore, m= 9 is the correct answer!