Problem

Solve $2 x(6-5 x)=-7$ Give your answers to 2 d.p.

Solution

Step 1 :Expand the equation: \(2x(6-5x) = 2x(6) - 2x(5x) = 12x - 10x^2\)

Step 2 :Set the equation equal to -7: \(12x - 10x^2 = -7\)

Step 3 :Rearrange the equation: \(10x^2 - 12x + 7 = 0\)

Step 4 :Use the quadratic formula to solve for x: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)

Step 5 :Plug in the values: \(x = \frac{12 \pm \sqrt{(-12)^2 - 4(10)(7)}}{2(10)}\)

Step 6 :Simplify the expression: \(x = \frac{12 \pm \sqrt{144 - 280}}{20}\)

Step 7 :Further simplify: \(x = \frac{12 \pm \sqrt{-136}}{20}\)

Step 8 :Calculate the two solutions: \(x = \frac{3}{5} - \frac{\sqrt{106}}{10}, x = \frac{3}{5} + \frac{\sqrt{106}}{10}\)

Step 9 :Round the solutions to 2 decimal places: \(x = -0.43, x = 1.63\)

Step 10 :\(\boxed{x = -0.43, x = 1.63}\)

From Solvely APP
Source: https://solvelyapp.com/problems/15853/

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