If you want to find the x-intercept, you replace y in the equation with 0 and solve the equation for x.
If you want to find the y-intercept, you replace x in the equation with 0 and solve the equation for y.
Example:
[tex]y=2x+5\\\\
\hbox{x-intercept}\\
0=2x+5\\
2x=-5\\
x=-2.5\\
\hbox{x-intercept is } (-2.5,0)\\\\
\hbox{y-intercept}\\
y=2\cdot0+5\\
y=5\\
\hbox{y-intercept is }(0,5)[/tex]