What value for c will make the expression a perfect square trinomial? x^2-7x+c

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

Pls! does anybody know a shortcut for answering these types of questions in the future?

Alogical argument that is presented in graphical form using boxes and arrows is called?