Question

Diagram 7 shows a trapezium ABCD. The straight lines AB and CD are parallel.Find

(a) the equation of the straight lines CD

(b)the x-intercept for the straight line CD

Answer 1

see explanation

Explanation:

(a)

Since lines AB and CD are parallel then their slopes are equal

y = -
`(1)/(2)` x + 14 is in slope- intercept form ( y = mx + c )

with slope m = -
`(1)/(2)`

Hence slope of CD = -
`(1)/(2)`

D is the point (0, 7) ⇒ c = 7

y = -
`(1)/(2)` x + 7 ← equation of CD

(b)

to find the x- intercept let y = 0, in the equation and solve for x

-
`(1)/(2)` x + 7 = 0 ( multiply through by 2 )

- x + 14 = 0 ⇒ - x = - 14 ⇒ x = 14 ← x- intercept of CD