Which equations are ture for the values of x, y, and a select three options... pls help

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Which of the following contains a variable?

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

Nellie is analyzing a quadratic function f(x) and a linear function g(x). will they intersect? f(x) g(x) graph of the function f of x equals one half times x squared, plus 2 x g(x) 1 5 2 10 3 15