Concept:The value of u is the y-coordinate on the quadratic curve when x=−2.5.So substitute x=−2.5 into the curve equation y=2x2+x−1.Explanation:The curve has equation y=2x2+x−1.Put x=−2.5 in the equation:u=2(−2.5)2+(−2.5)−1First, (−2.5)2=6.25.So, 2(6.25)=12.5.Therefore, u=12.5−2.5−1.Simplify: 12.5−3.5=9.0.Hence, the point on the curve at x=−2.5 has value u=9.0.Answer:u=9.0Correct option: C. y=9.0
