In the U.S., a dental crown costs between \( \$ 600 \) and \( \$ 3,000 \). In Costa Rica, a crown is the equivalent of about one-third the cost in the U.S.. Write an inequality for the possible cost \( (x) \) of a dental crown in Costa Rica.

(c) \( 3 x^{2}-x=x^{2}-5 x+6 \)

Rationalize the Denominator: \( \frac{7+\sqrt{5}}{2+\sqrt{5}} \)

Linear Application The function \( E(t)=3848-77.1 t \) gives the surface elevation (in feet above sea level) of Lake Powell \( t \) years after 1999. Interpret the Slope in this situation. The surface elevation of Lake Powell is Select an answer \( \vee \) at a rate of

(c) \( 3 x^{2}-x=x^{2}-5 x+6 \)

Students stuff envelopes for extra money. Their initial cost to obtain the information for the job was \( \$ 420 \). Each envelope costs \( \$ 0.03 \) and they get paid \( \$ 0.06 \) per envelope stuffed. Let \( x \) represent the number of envelopes stuffed. (a) Express the cost \( C \) as a function of \( x \). (b) Express the revenue \( R \) as a function of \( x \). (c) Determine analytically the value of \( x \) for which revenue equals cost. (a) \( C(x)=\square \) (C in dollars) (b) \( R(x)=\square \) ( \( R \) in dollars) (c) Revenue equals cost when \( x=\square \)