Solve by substitution: 5x+y=-13 and y=7

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

27 is what percent of 108? 27 is % of 108

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)