SOLUTION: Hi I need help with these questions: 1. -9+i/-9-3i I divided the num and dem by the recip -9+3i and then used FOIL is that correct then simplified My answer was 13/15-3i/

Question 211101: Hi I need help with these questions:
1. -9+i/-9-3i I divided the num and dem by the recip -9+3i and then used FOIL is that correct then simplified My answer was 13/15-3i/15 help
2. x^-6x+17=0 Do I use the quadr formula to solve this I did and got 4-i and 4+i
3. (x^+3x)+5=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)
4. (x^-2x)+7=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)
5. (x^+2x)+7=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
I'll do the first three to get you going. The rest will be like # 2 and # 3

# 1

Start with the given expression.

Multiply the fraction by .

Note: is the complex conjugate of . Multiplying two conjugate pairs will result in a real number.

Combine the fractions.

FOIL the numerator.

FOIL the denominator.

Multiply.

Replace with -1

Multiply

Combine like terms.

Break up the fraction.

Reduce.

So .

So the expression is now in standard form where and

# 2

Start with the given equation.

Notice that the quadratic is in the form of where , , and

Let's use the quadratic formula to solve for "x":

Start with the quadratic formula

Plug in , , and

Negate to get .

Square to get .

Multiply to get

Subtract from to get

Multiply and to get .

Simplify the square root (note: If you need help with simplifying square roots, check out this solver)

Break up the fraction.

Reduce.

or Break up the expression.

So the solutions are or

# 3

Start with the given equation.

Notice that the quadratic is in the form of where , , and

Let's use the quadratic formula to solve for "x":

Start with the quadratic formula

Plug in , , and

Square to get .

Multiply to get

Subtract from to get

Multiply and to get .

Simplify the square root (note: If you need help with simplifying square roots, check out this solver)

or Break up the expression.

So the solutions are or

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