Which of the following quadrilaterals have diagonals that are perpendicular to each other ?

Can someone explain the elimination method to me for this problem?

Colin listed his assets and liabilities on a personal balance sheet. colin’s balance sheet (august 2013) assets liabilities cash $1,500 credit card $500 stocks $800 rent $800 car $5,000 car loan $1,200 coin collection $1,200 student loan $5,000 total total which statement is true about the total assets and the total liabilities? the total of the assets and the liabilities are the same. the total of the assets is greater than the total of the liabilities. the total of the assets is less than the total of the liabilities. the total of the assets cannot be compared to the total of the liabilities.

The system of equations graphed below has how many solutions? y = 2x + 2