Let x be a value such that 9x^2-18x-16=0 and 15x^2+28x+12=0 What is the value of x? Express your answer as a simplified common fraction.
So I'm guessing that you want x to follow both of these equations, if not, please correct your question.
Now using the quadratic equation the roots of 9x^2-18x-16=0 would be 8/3 or -2/3
Now we do the same for 15x^2+28x+12=0 and we get: -2/3 or -6/5
Notice that both of the equations have a root of -2/3 thus -2/3 is your answer