Solve 2x^2 - 3x - 1 = 0, using the quadratic formula. Give your answer to two decimal places.

To start, let us recall the form of a quadratic equation. y = ax2 + bx + c. When making x the subject of the formula and setting y = 0, we get the quadratic formula, as you may have seen before. x = (-b +- sqrt(b2 - 4ac) )/2a. From our question, we see that a = 2, b = -3, c = -1. We can now plug this into our formula for an answer! We get that x = ( 3 +- sqrt(32 - 4(2)(-1) )/2(2). Solving this and making our root positive we get x = 1.78 (2 dp). Setting our root as negative we get x = -0.28 (2 dp).

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Answered by Jason W. Maths tutor

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