Question

If x + y equals to 10 and X Minus y equals to 5 find the value of 2 y

Answer 1

if x + y equals to 10 and X Minus y equals to 5 find the value of 2 y ​

So, we have

`\begin{gathered} x+y=10\text{ Equation (1)} \\ x-y\text{ = 5 Equation (2)} \\ 2y\text{ = ?} \\ \end{gathered}`

to solve this, we can add the equations

Equation 1 +Equation 2

`\begin{gathered} \text{ x + y = 10} \\ \text{ x - y = 5} \\ 2x=15 \\ x=(15)/(2) \\ x=7.5 \\ \end{gathered}`

Now, replace this value in equation 2 to find y

`\begin{gathered} \text{ x - y = 5} \\ 7.5-y\text{ =5} \\ 7.5-5=y \\ y=2.5 \\ \end{gathered}`

Now, 2y

`\begin{gathered} 2y=2\cdot2.5 \\ 2(2.5)=5 \end{gathered}`

So, 2y=5