Question

what constant number must be added and is extracted to 4 x square + 12 x + 8 is equal to zero to solve it by method of completing the square​

Answer 1

Solving the problem by completing the square method

4x²+12x + 8 = 0     ( Dividing the whole equation by 4)

x²+3x + 2 = 0       (Sending 2 to the RHS)

x²+3x = -2   (Putting x² + 3x into the formula a²+2ab + b² )

x² + 2 × x × 3/2  = -2   (here we have divided 2 with 3 just to make the eq equal to the previous one)

x² + 2 × x × 3/2 + (3/2)² = -2 + (3/2)²  {By adding (3/2)² on both sides}

(x+3/2)² = -2 = 9/4   { Now we can write x² + 2 × x × 3/2 + (3/2)² = (x+3/2)² }

(x+3/2)² = -8/4+9/4

(x+3/2)² = 1/4      (Under rooting both sides)

x+3/2 = √1/4

x+3/2 = 1/2

x = 1/2 - 3/2

x = -2 / 2

x = -1  

That's the answer Friend.

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