The combined mass of two trucks is 29 tonnes. The heavier truck is 1 tonne less than twice the mass
of the smaller truck. Write two equations and solve them to find the mass of each truck.

Mass of the smaller truck is 10 tonnes and that of the heavier truck is 19 tonnes.

Step-by-step explanation:

⇒ x + 2x - 1 = 29

⇒ 3x - 30 = 0

⇒ 3x = 30

⇒ x = 10 tonnes

and 2x - 1 = 20 - 1 = 19 tonnes

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value