Question 482184
as you are given m=-3, slope/gradient=-3

Also m=(y-y1) / (x-x1)

therefore -3=y-(-2) / x-1 where y1=-2, x1=1, ie : (-2,1)

Cross multiply, -3(x-1)=y-(-2)

expand and simplify  -3x+3=y+2

do -2 both side -3x+3-2=y+2-2

tidy up -3x+1=y

swap sides y=-3x+1

because the equation is in the form of y=mx+c

slope = co-efficient of x and intercept=c, constant

Again as you can see slope/gradient=-3 and intercept=1

I hope that answer is clear. Try doing it again and again. Also practise similar questions to understand more.