[tex]4y = 2x - 10[/tex]
Make X the subject of the formula
Add 10 to both sides
[tex]4y + 10 = 2x[/tex]
divide by 2 in both sides
[tex] \frac{4y + 10}{2} = x[/tex]
So X =( 4y +10 )÷2
They are saying that y=6
Now substitute the equation given with the values
[tex]x = \frac{(4 \times 6) + 10}{2} [/tex]
[tex]x = \frac{24 + 10}{2} [/tex]
[tex] x = \frac{34}{2} [/tex]
[tex]x = 17[/tex]
Here you go