Question

If a line with a slope of -2 crosses the y-axis at (0, 3), what is the equation of the line?

Answer 1

Answer: $2x+y-3=0$

Step-by-step explanation:

The equation of a line passing from points (a,b) and has slope m is given by :-

$(y-b)=m(x-a)$

Given : Slope of a line = -2

Point = (0,3)

Then , the equation of a line passing from points (0,3) and has slope -2 is given by :-

$(y-3)=-2(x-0)\\\\\Rightarrow\ y-3=-2x\\\\\Rightarrow\ 2x+y-3=0$

Hence, the equation of the line : $2x+y-3=0$

Answer 2

The slope-intercept form: y = mx + b

m - the slope
b - the y-intercept

m = -2; (0; 3) → b = 3

subtitute

y = -2x + 3