Step-by-step explanation:
We have got the lines :
Both lines intercept the x-axis in the point :
In all point from x-axis the y-component is equal to 0.
We replace the I point in the lines equations:
From the first equation :
From the second equation :
Then
Finally :
y = ax + b and y = cx + d have the same x-intercept ⇔ad=bc
