In a linear equation ax+by+c=0, what is the slope?

a_1 = -2 (slider from -10 to 10, step 1)
b_1 = 1 (slider from -10 to 10, step 1)
c_1 = 5 (slider from -20 to 20, step 1)
Line1: (a_1 * x) + (b_1 * y) + c_1 = 0
D = Intersect(Line1, yAxis)
E = Intersect(Line1, xAxis)
Text1: "Equation of the line is ax+by+c=0, which is " + a_1 + "x+" + b_1 + "y + " + c_1 + " = 0
Slope of the line is -a/b, which is  -(" + a_1 + "/ " + b_1 + ") 
Y axis intercept is -c/b, which is -(" + c_1 + "/" + b_1 + ") - Point D
X axis intercept is -c/a, which is -(" + c_1 + "/" + a_1 + ") - Point E"
a = false

Tool: SquareTool
Tool2[ <Number>, <Point> ]
Input: side, A
Output: poly1

B = Point(Circle[A, side])
a = Segment(A, B)
c = Circle(A, side)
b = OrthogonalLine(A, a)
C = Intersect(c, b, 2)
d = Circle(C, side)
e = OrthogonalLine(C, b)
D = Intersect(d, e, 1)
poly1, a_1, b_1, d_1, c_1 = Polygon(A, B, D, C)