using the formula
[tex]y - y1 = m(x - x1)[/tex]
where m is the slope or gradient
from the question, x1 = -1 and y1 =5
and gradient/slope m = 3
substituting them in the formula
[tex]y - 5 = 3(x - ( - 1))[/tex]
[tex]y - 5 = 3(x + 1)[/tex]
[tex]y - 5 = 3 x + 3[/tex]