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Solve x^2+11x+121/4=125/4 for x

User BrianO
by
7.4k points

2 Answers

5 votes

Answer:

Explanation:

ANSWER :) x=-11/2+5 Sq root 5/2

(D) on edge

User OLen
by
6.8k points
1 vote

Answer


x=(-11+5√(5) )/(2) ,x=(-11-5√(5) )/(2)

Explanation

Let's solve our quadratic equation step by step.

Step 1. Subtract
(125)/(4) from both sides


x^2+11x+(121)/(4)= (125)/(4)


x^2+11x+(121)/(4)-(125)/(4)= (125)/(4)-(125)/(4)


x^2+11x-1=0

Step 2. Complete the square

Using the formula for completing the square:


x+bx+c=(x-h)^2+k

where


h=(-b)/(2)


k=c-(b^2)/(4)

We can infer from
x^2+11x-1=0 that
b=11 and
c=-1, so let's find
h and
k:


h=(-b)/(2)


h=(-11)/(2)


k=-1-(11^2)/(4)


k=-1-(121)/(4)


k=-(125)/(4)

Now we can replace the values in our formula:


x+bx+x=(x-h)^2+k


x^2+11x-1=(x-(-(11)/(2) ))^2+(-(125)/(4) )


x^2+11x-1=(x+(11)/(2) )^2-(125)/(4)


(x+(11)/(2) )^2-(125)/(4)=0

Step 3. Add
(125)/(4) to both sides


(x+(11)/(2) )^2-(125)/(4)+(125)/(4)=0+(125)/(4)


(x+(11)/(2) )^2=(125)/(4)

Step 4. Take square root to both sides


x+(11)/(2) =+or-\sqrt{(125)/(4) }


x+(11)/(2)=+or-(5√(5) )/(2)

Step 5. Subtract
(11)/(2) form both sides


x+(11)/(2)-(11)/(2) =+or-(5√(5) )/(2)-(11)/(2)


x =+or-(5√(5) )/(2)-(11)/(2)

Solutions of the equation:


x=(-11+5√(5) )/(2) ,x=(-11-5√(5) )/(2)

User RaviRokkam
by
6.1k points
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