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The first few steps in solving the quadratic equation 5x2 + 27x = 14 − 13x by completing the square are shown.

5x2 + 27x = 14 − 13x

5x2 + 40x = 14

5(x2 + 8x) = 14

Which is the best step to do next to solve the equation by completing the square?

User Adigioia
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2 Answers

4 votes

Answer:

5(x2 + 8x + 16) = 94

Explanation:

User Sdfadfaasd
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4 votes

Answer:

Explanation:

Give the equation 5x² + 27x = 14 − 13x, we are to write the steps needed to solve for x using the completing the square method.

Step 1: Rewrite the equation in a quadratic form by first adding 13x to both sides of the equation.

5x² + 27x +13x= 14 − 13x+13x

5x² + 40x = 14

Step 2: factor out the common constant in the left hand side of the equation.

5(x²+8x) = 14

Step3: The next step to take is to divide through by the the value of 5 to have;

5(x²+8x)/5 = 14/5

x²+8x = 14/5

Step 4: complete the square of the equation at the left hand side by adding the square of half of the coefficient of x to both sides i.e {1/2(8)}² which is 4²

x²+8x +4² = 14/5+4²

x²+8x +16 = 14/5+16

(x+4)² = 94/5

Step 5: Taking the square root of both sides

√(x+4)² = ±√94/5

x+4 = ±√94/5

Step 6: subtract 4 from both sides

x+4-4 = ±√94/5 - 4

x = ±√94/5 - 4

Hence the solution to the equation using completing the square method is x = -4±√94/5

User Kenroy
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