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Rajah
√(x+4)+√(2x+6)=7
rsmith almost gets the question right. (a+b)^2 = a^2 + 2ab + b^2,
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.
@ 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 ?
dont u got to do the one and the ( and here first then u have to to keep bringing it down
till u get ur answer or change keep oppisite
@oojih where are you going with your solution?
i think am right yay
Just square both sides: 3x+10+ 2 sqrt(......=49) etc etc.
@ 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.
yes x^2 + 102x + 2601 = 196(2x+6) does look nasty
\[ x+ 51 = 14 \sqrt{2x+6} \] \[ (x+51)^2 = 14^2 (2x+6) \] yes..mr rajah can solve this fun quadratic equation
check out http://www.oojih.com/displaypage/algebra/ for more algebra study guide and practice test.
you are right oojih. :) roots are 285 and 5. 285 is not sensible so the root being 5 works
sqrt(5+4) + sqrt(2*5+6) =7 sqrt(9) + sqrt(16) = 3 + 4 = 7... yaayy, good job rsmith
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.