Question

Solve the following equation using the completing the square method: x2+8x=3

Answer 1

Answer:

Step-by-step explanation:

Divide the coefficient of x by 2

8/2 = 4. Now find the square of 4 = 4² = 16

Add 16 to both sides of the equation

x² + 8x + 16 = 3  + 16

x² + 2* x * 4 + 4² = 19

{Compare with a² + 2ab + b² = (a + b)² }

(x + 4)² = 19

Both sides take square root,

$\sqrt{(x+ 4)^{2}}=\sqrt{19}\\\\x + 4 = \sqrt{19}$

x + 4 = ± 4.36

x + 4 = 4.36   ; x +  4 = -4.36

x = 4.36 -4     ;    x  = -4.36 - 4

x = 0.36         ; x = - 8.36

Answer 2

Answer:

x= plus or minus square root of 19 -4

Step-by-step explanation:

x^2+8x ___=3

take half of your b term (8) and then multiply by two and add or subtract it to both sides

x^2+8x+16=3+16

then combine like terms

x^2+8x+16=19

then factor your quadratic equation

(x+4)^2=19

now solve for x

take the square root of (x+4)^2 to get rid of the ^2

you then also have to square the 19 because what you do to one side you have to do to the other

(x+4)= square root of 19

subtract 4 from both sides

x= plus or minus square root of 19 -4