## Rajah Group Title √(x+4)+√(2x+6)=7 3 years ago 3 years ago

1. oojih.com Group Title

rsmith almost gets the question right. (a+b)^2 = a^2 + 2ab + b^2,

2. oojih.com Group Title

this is how I'd approach it: $\sqrt{x+4} = 7 - \sqrt{2x+6}$ $x+ 4 = 49 + (2x+6)-14 \sqrt{2x+6}$ $x + 4 -49 -2x-6=-14\sqrt{2x+6}$ $-x -51 = -14\sqrt{2x+6}$ $x+51 = 14\sqrt{2x+6}$ I am sure you can continue and solve this equation now.

3. oojih.com Group Title

@ rsmith, you can validate whether your answer is correct by plugging x=13 into the equation sqrt(13+4) + sqrt(2*13+6) =7 sqrt(17) + sqrt(32) = 7 ?

4. alice_smith Group Title

dont u got to do the one and the ( and here first then u have to to keep bringing it down

5. alice_smith Group Title

till u get ur answer or change keep oppisite

6. rsmith Group Title

@oojih where are you going with your solution?

7. alice_smith Group Title

i think am right yay

8. estudier Group Title

Just square both sides: 3x+10+ 2 sqrt(......=49) etc etc.

9. oojih.com Group Title

@ rsmith, you need to square the equation one more time to get rid of the square toot, then it boils down to a quadratic equation whic looks prett nasty from the number.

10. alice_smith Group Title

11. alice_smith Group Title

u confuse me

12. rsmith Group Title

yes x^2 + 102x + 2601 = 196(2x+6) does look nasty

13. alice_smith Group Title

am correct

14. oojih.com Group Title

$x+ 51 = 14 \sqrt{2x+6}$ $(x+51)^2 = 14^2 (2x+6)$ yes..mr rajah can solve this fun quadratic equation

15. oojih.com Group Title

check out http://www.oojih.com/displaypage/algebra/ for more algebra study guide and practice test.

16. rsmith Group Title

x^2 - 290x +1425 = 0

17. rsmith Group Title

you are right oojih. :) roots are 285 and 5. 285 is not sensible so the root being 5 works

18. oojih.com Group Title

sqrt(5+4) + sqrt(2*5+6) =7 sqrt(9) + sqrt(16) = 3 + 4 = 7... yaayy, good job rsmith

19. oojih.com Group Title

I command you for solving the quadratic equation..:) This is a good math question, but the number should be made simpler so that students get the concept instead of being bogged down by this ugly number.

20. rsmith Group Title

true that