What is the slope intercept form for
7y+42=-14x

Working:
7y + 42 = -14x
7y = -14x - 42
y = ((-14x - 42) ÷ 7) 
Expand and Simplify:
y = -2x - 6
Factorise:
y = -2(x +3)
x =  -3
Substitute x=-3 into equation.
7y + 42 = -14(-3)
7y + 42 = 42
7y = 0
Divide 7, on both sides, to get rid of the coefficient (7), thus, making y the subject.
y = 0     [anything divide or times to zero, will always remain zero]
Following model: (x,y)
(-3,0)

Hope this helps. Chur :)

A . 0.8

   - The fraction 8/10 is equal to 8 divided by 10 which is equal to 0 . 8 in decimal form .