## anonymous 5 years ago Solve the equation. square root of 5x+1=6 square root of x-2 +7=-4 x2+7x+4=0 5x2=-15

1. anonymous

1) x=7 2) x=123 3) x=-6.37, -.63 4) x=9

2. anonymous

how did u get these answers

Would like to see how the answer to the 4th one was developed. when 9 is substitued in the equation: $5(9)^{2}=-15$ $(9)^{2}=-15/5=-3$ $81\neq-3$

4. anonymous

Gettin there...... how about $i \sqrt{3}$

6. anonymous

$5x ^{2}= -15$ $X ^{2}= -15\div5=-3$ $X=\sqrt{-3}$ $X= i \sqrt{3}$

7. anonymous

Sorry about that, I'm new to this and I hadn't yet figured out the equation inserts.

What method did you use on number 3. Did you use quadratic formula?

9. anonymous

Yes. First I put it in the equation and solved, simplifying tona decimal and rounding to the nearest hundredth. I also checked the zeroes on the graph.

10. anonymous

5x^2 = -15 x^2 = -3 take the square root x = +- i sqrt(3)

Very good. lerachia is there any more questions?

blexting thanks , so their is two answers for number 4 $i \sqrt{3}$$-i \sqrt{3}$

lerachia, do you understand how quantum torch got those answers or do you care?

14. anonymous

Yes, when you move an even power (either the numerator or denominator) there are multiple answers. I don't know how to write that with the equation thing yet though, but the rule applies, so thanks on my part as well.

good night all.

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