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October 21, 2014

October 21, 2014

Posted by **Robert** on Friday, November 16, 2012 at 12:46pm.

12. Use the quadratic formula to solve the equation. 4x2–6x–10=0

13. Simplify the number using the imaginary unit i. Square root of -16

14. Simplify the expression. -5+i/2i

15. What is the solution of the linear-quadratic system of equations?

y=x^2+5x-3

y-x=2

- Algebra 2 -
**Steve**, Friday, November 16, 2012 at 2:32pm#12 just plug in the numbers

x = (6±√(36+160))/8

= (6±14)/8

= 6/8 + 14/8 or 6/8 - 14/8

= 5/2 or -1

#13

√-16 = √(16 * -1) = √16√-1 = 4i

#14

since i*i = -1, 1/i = -i

(-5+i)/2i = -5/2i + i/2i = 5/2 i + 1/2

or, in standard form, 1/2 + 5/2 i

#15

looking at the 2nd equation, y = x+2, so

x+2 = x^2+5x-3

x^2 + 4x - 5 = 0

(x+5)(x-1) = 0

x = -5 or 1

so, y = -3 or 3

the solutions are thus (-5,-3)(1,3)

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