a$)$ A manufacturer sells a product at a price of RM$150$ per unit. The labour and material

costs are RM$20$ and RM$45$ per unit respectively. The rental of a building is

RM$11,050.$ Find break$-$even quantity.

b$)$ Prove either $2x+y=4$ and $4x+2y=9$ are parallel or perpendicular lines.