Each side of a square measures 15m. Solve for its area

What is the slope of the line shown below?

Choose the equation that represents the graph below: (1 point) graph of a line passing through points negative 3 comma 0 and 0 comma 3 y = x − 3 y = −x + 3 y = −x − 3 y = x + 3 will award !

Having a hard time understanding this question (see attachment).