Question

7x-4y=20 for y when x=3

Answer 1

$y=0.25$ or $\frac{1}{4}$; you first need to plug in the $x$ value, making the equation $7(3)-4y=20$. Multiply $7$ and $3$ to get $21$ and then subtract it from $20$ in order to isolate the $y$. This results in $-4y=-1$. Then divide both sides by $-4$ and the answer would be $\frac{1}{4}$, since dividing two numbers that have the same sign results in a positive number and $\frac{1}{4}$ can not be simplified any further, unless you are looking for the answer in decimal form, in which $y=0.25$.

Answer 2

Y= 1/4 because 7(3)-4(1/4)