SOLUTION: I am stumped...I can not figure these two problems out for the life of me...can someone please assist me with these two problems? Find all real solutions to each equation. 64

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Question 211413This question is from textbook Elementary and Intermediate Algebra, 3e
: I am stumped...I can not figure these two problems out for the life of me...can someone please assist me with these two problems?
Find all real solutions to each equation.
64) x%5E2+%2B+x+%2B+sqrt+%28x%5E2+%2B+x%29+-+2+=+0
Find all real and imaginary solutions to each equation.
70) b%5E4+%2B+13b%5E2+%2B+36+=+0
This question is from textbook Elementary and Intermediate Algebra, 3e

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
I am stumped...I can not figure these two problems out for the life of me...can someone please assist me with these two problems?
Find all real solutions to each equation.

x%5E2+%2B+x+%2B+sqrt+%28x%5E2+%2B+x%29+-+2+=+0 

We group the first two terms as one term:

%28x%5E2+%2B+x%29+%2B+sqrt+%28x%5E2+%2B+x%29+-+2+=+0

Now there are three terms on the left.  Notice 
that if we square the variable of the
middle term sqrt%28x%5E2%2Bx%29, we get the 
variable of the first term %28x%5E2%2Bx%29.

Therefore we substitute the letter "u" for
the variable of the middle term, that is

sqrt%28x%5E2%2Bx%29=u

Then squaring both sides we have

%28x%5E2%2Bx%29=u%5E2

So we substitute and

%28x%5E2+%2B+x%29+%2B+sqrt+%28x%5E2+%2B+x%29+-+2+=+0

becomes simply

u%5E2%2Bu-2=0

Which we factor 

%28u%2B2%29%28u-1%29=0

and solve getting u=-2 and u=1

Since sqrt%28x%5E2%2Bx%29=u and a square root
can never be negative in real numbers, we can 
rule out u=-2. So u=1

Substituting back

%28x%5E2%2Bx%29=u%5E2

becomes

%28x%5E2%2Bx%29=1%5E2
x%5E2%2Bx=1
x%5E2%2Bx-1=0

We use the quadratic formula:

 x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ 

 x+=+%28-%281%29+%2B-+sqrt%28+%281%29%5E2-4%2A%281%29%2A%28-1%29+%29%29%2F%282%2A%281%29%29+

 x+=+%28-1+%2B-+sqrt%28+1%2B4+%29%29%2F2+

 x+=+%28-1+%2B-+sqrt%285%29%29%2F2+

--------------------------------

Find all real and imaginary solutions to each equation. 
70) b%5E4+%2B+13b%5E2+%2B+36+=+0

Notice that if we square the variable of the
middle term sqrt%28b%5E2%29, we get the 
variable of the first term %28b%5E4%29.

Therefore we substitute the letter "u" for
the variable of the middle term, that is

b%5E2=u

and squaring both sides:

b%5E4=u%5E2

So we substitute and

b%5E4+%2B+13b%5E2+%2B+36+=+0

becomes simply

u%5E2%2B13u%2B36=0

Which we factor 

%28u%2B9%29%28u%2B4%29=0

and solve getting u=-9 and u=-4

Now since b%5E2=u, we have

b%5E2=-9 and b%5E2=-4

Taking square roots:

b=%22+%22%2B-sqrt%28-9%29 and b=%22+%22%2B-sqrt%28-4%29

or

b3i and b2i

Edwin