Question

2. Two lines are represented by equations: 2x + 4y = 21 and y = kx - 12. What value of k will

make lines parallel?

Answer 1

-1/2

Explanation:

- arrange the equation in the y=mx+b form

2x + 4y =21, subtract 2x from both sides of the equation

4y= -2x +21 , divide both sides by 4

y= -1/2x +21/4

-compare the slopes m of the 2 equations

y= kx -12, has the slope k

y= -1/2x +21/4, has the slope -1/2

- If the lines are parallel then they have the same slope

Therefore, k= -1/2