Question

Four pine seedling and 3 fir seedlings cost 29.00. Two pine seedlings and 7 fir seedlings cost $42.00 Determine the cost of each type of seedling.

Answer 1

4p + 3f = 29
2p + 7f = 42

Multiply the second equation by -2 to get:

4p + 3f = 29
-4p -14f = -84

Now, you are authorized to add. (You can only add when eliminating a variable):

-11f = 55

11f = -55
f = -55/11
f = -5

Now find p

Answer 2

But why do we mulitipy it by negative 2?

Answer 3

@Hero

Answer 4

?

Answer 5

Because you need to do that in order to eliminate a variable