Question

If x=2y+1 what is th e value of 10y-5x

Answer 1

$x=2y+1$

what is $10y-5x$?

all you gotta do is substitute the value of $x$ in the equation:

$x=2y+1\\10y-5(2y+1)$

now solve for $y$:

$10y-5(2y+1)\\10y-10y-5=-5$

so the value of $10y-5x =$ $\boxed{-5}$