Calculate:
3 pounds (lbs) =——grams (g)

In the equations, a and b represent the price per night for a room in hotel a and hotel b, respectively, w weeks after september 1 last autumn. what was the price per night in hotel a when it was equal to the price per night in hotel b? a = 240 − 20w b = 320 − 30w

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).