Question

I need help finding out how to figure out what s equals in the problem 2/3s+5/6s=21(I work best with decimals)

Answer 1

s=14

Step-by-step explanation

`(2)/(3)s+(5)/(6)s=21`

Step 1

remember how to sum fraction numbers

`(a)/(b)+(c)/(d)=(ad+bc)/(bd)`

factorize s and sum the fraction numbers

`\begin{gathered} (2)/(3)s+(5)/(6)s=21 \\ s((2)/(3)+(5)/(6))=21 \\ s((12+15)/(18))=21 \\ s((27)/(18))=21 \\ s((3)/(2))=21 \\ (3)/(2)s=21 \end{gathered}`

Step 2

multiply both sides by 2/3

`\begin{gathered} (3)/(2)s=21 \\ (3)/(2)s\cdot(2)/(3)=21\cdot(2)/(3) \\ (6)/(6)s=(42)/(3) \\ \\ s=14 \end{gathered}`

so, the answer is s= 14