Question

3x + ky = 8

X – 2ky = 5
are simultaneous equations where k is a constant.
a) Show that x = 3.
b) Given that y = 1/2 determine the value of k.

Answer 1

a) 3x + ky = 8

ky = 8 - 3x

x – 2ky = 5

x - 2(8 - 3x) = 5

x - 16 + 6x = 5

7x = 21

x = 3 (shown)

b) x-2ky = 5

sub x = 3, y = 1/2

3-2k(1/2) = 5

-2k = 2

k = -1