Which graph represents the function f(x)=2x/x^2-1

What expression is equivalent to (84+16)

Isaac wants the equation below to have no solution when the missing number is placed in the box. which number should he place in the box?

If it 8 inch candle burns at 7/10 inch per hour and a 6 inch candle burns at 1/5 inch per hour after how many hours would both candles be the same height