Question

Find the two points where the the line crosses the x and y axis for the given equation.

a) ax + by = c
b) ax - by = c

Answer 1

To figure out where each crosses the x and y axis simply plug in 0 for y and x respectively.

x intercept is where y = 0
y intercept is where x = 0

a) x intercept

ax + b(0) = c

c = ax

x = c/a so the x intercept is (c/a, 0)

y intercept

a(0) + by = c
0 + by = c
y = c/b, so the y intercept is (0,c/b)

Jus repeat the process for part b

b) x intercept
ax - 0 = c
x = c/a, so the x intercept is the same, (c/a , 0)

y intercept

0 - by = c
y = -c/b, so the y intercept is different from before (0, -c/b)