Mathematics
sotonoemie10
2015-11-01 04:29:54
what is 2x+square root x+1=8 solve for x
ANSWERS
jenjen28
2015-11-01 07:29:12

[latex]f 2x+sqrt{x+1}=8implies sqrt{x+1}=8-2xquad leftarrow extit{now we square both sides} \\\ (sqrt{x+1})^2=(8-2x)^2implies x+1=8^2-32x+(2x)^2 \\\ x+1=64-32x+2^2x^2implies x+1=64-32x+4x^2 \\\ 0=4x^2-32x-x+64-1implies 0=4x^2-33x+63 \\\ 0=(4x-21)(x-3)implies egin{cases} 0=4x-21\ 21=4x\\ oxed{frac{21}{4}=x}\ --------\ 0=x-3\ oxed{3=x} end{cases}[/latex]

belledevault
2015-11-01 07:30:27

Hello, On my keybord i have no touch "square root (√)" but "V" yes . [latex]2x+ sqrt{x+1} =8\ sqrt{x+1} =8-2x\ x+1=(8-2x)^2\ x+1=64-32x+4x^2\ 4x^2-33x+63=0\ x= frac{21}{4} or x=3\ [/latex] Verification: if x=3 then 2*3+√(3+1)=6+2=8 if x=21/4 then 13≠8 is to exclude.

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