hello!
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We are given:-
Slope :- -7
y-intercept:- 4
To find:-
the line's equation (in slope intercept form)
Slope intercept form looks like so:-
y=mx+b
where
m -> slope & b -> y-intercept
Plug in the values:-
(instead of m, plug in -7, and instead of b, plug in 4:

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note:-
Hope everything's clear; if you need any clarification/explanation, kindly let me know, and I will comment and/or edit my answer :)