Writing a function that expresses f(x). 8100 square feet

Afruit stand has to decide what to charge for their produce. they need $10 for 4 apples and 4 oranges. they also need $15 for 6 apples and 6 oranges. we put this information into a system of linear equations. can we find a unique price for an apple and an orange?

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?

Solve the equation for x.3(6x - 1) = 12 i've tried doing the math and i can't find out what i'm doing wrong