Maths homework help?

Question

I got a question X(squared) +5X +2 =0 I need to complete the square or somthing can someone help me

Answer 1

x^2 +5x + 2 = 0
step 1 transpose 2 to the other side:
x^2 + 5x = -2

step 2 Add a 3rd term on the left side to complete the square, how? Divide the coefficient of x by 2 and square the quotient. Whatever is done on the left must also be don on the right in order not to change the meaning of the equation:
x^2 +5x +25/4 = -2 +25/4

Step 3: Simplify further
x^2 +5x +25/4 = (-4 +25)/ 4
x^2 +5x +25/4 = 21/4

Step 4 Express the left side as a square of a sum of a binomial
(x+ 5/2)^2 = 21/4

Step 5 Extract the square root of both sides
x + 5/ 2 = positive or negative (square root of 21)/ 2

Step 6 Solving for x :
x = (square root of 21)/ 2 -5/2
x = + (square root of 21)/ 2 -5/2 and -(square root of 21)/ 2 -5/2

Answer 2

You need to make your polynom. a complete square of the form
(X+A)^2+C=0
>X^2+2*A*X+A^2+C=0
>2*A=5 equating coeff, or A=5/2
>A^2+C=2..or C=-17/4
>(x+5/2)^2-17/4=0
>x=(-5+/-sqrt(17))/2

Answer 3

x² +5x +2 = 0

x² +5x = -2

Complete the square

x² +5x + (5/2)² = (5/2)² - 2

(x + 5/2)² = (25/4) - 2 = 21/4

x + 5/2 = ± (√21)/2

x = -(5/2) ± (√21)/2
.

Answer 4

(x+5/2)^2=x*x+5x+25/4=17/4 since 25/4-17/4=8/4=2 Now take sqrt of both sides. x+5/2=+/- sqrt[17/4] so x=-5/2+/-sqrt[17]/2

Answer 5

x^2+5x+2
=x^2+2*x*5/2+(5/2)^2+2-(5/2)^2
=(x+5/2)^2+2-25/4
=(x+5/2)^2-17/4 ans

Answer 6

the answers: x1= -0.44
x2 = -4.56
(it's correct, though you'd need the calculating way to satisfy your teacher) :D
sorry, too tired, too much to write so, take it or leave it:P