(1, - 2) and (5,10).....we can find the slope of a line connecttng these points thusly :
[ 10 - - 2 ] / [ 5 - 1 ] = 12 / 4 = 3
The equation of the said line is :
y = 3 ( x - 5) + 10
y = 3x - 15 + 10
y = 3x - 5 where this line crosses the y axis, x = 0....so
y = 3(0) - 5 = 0 - 5 = -5
So.....the line crosses the y axis at ( 0, - 5)
Here's a graph : https://www.desmos.com/calculator/eearzhfvuk