Using a euler circles to decide if the argument is valid
all cars use gasoline.
all things that use gasoline emit carbon dioxide.
some cars have four doors.
∴ some things with four doors emit carbon dioxide.

The argument is valid

Step-by-step explanation:

The explanation will be given in the image, where we see all propositions and which contains the other, showing that the argument is valid.

step-by-step explanation:

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^