Solved on Sep 29, 2023

Find the values of xx where y=x+x+6y=x+\sqrt{x+6} and y=6y=6.

STEP 1

Assumptions1. We have two equations y=x+x+6y=x+\sqrt{x+6} and y=6y=6 . We are to find all values of xx that satisfy both equations

STEP 2

Since both equations are equal to yy, we can set them equal to each other. This gives us a new equation to solve for xx.
x+x+6=6x + \sqrt{x+6} =6

STEP 3

We want to isolate the square root term, so we subtract xx from both sides of the equation.
x+6=6x\sqrt{x+6} =6 - x

STEP 4

To get rid of the square root, we square both sides of the equation. Remember that (ab)2=a22ab+b2(a-b)^2 = a^2 -2ab + b^2.
(x+6)2=(6x)2(\sqrt{x+6})^2 = (6 - x)^2

STEP 5

implify both sides of the equation.
x+=3612x+x2x + =36 -12x + x^2

STEP 6

Rearrange the equation to form a quadratic equation. A quadratic equation is in the form ax2+bx+c=0ax^2 + bx + c =0.
x213x+30=0x^2 -13x +30 =0

STEP 7

Factor the quadratic equation. We are looking for two numbers that multiply to 3030 and add to 13-13.
(x10)(x3)=0(x -10)(x -3) =0

STEP 8

Set each factor equal to zero and solve for xx.
x10=0andx3=0x -10 =0 \quad \text{and} \quad x -3 =0

STEP 9

olving the equations gives us two potential solutions for xx.
x=andx=3x = \quad \text{and} \quad x =3

STEP 10

We need to check these solutions in the original equation y=x+x+6y=x+\sqrt{x+6} to make sure they don't result in the square root of a negative number, as this would be undefined in the real number system.
For x=10x =10, we have y=10+10+6=10+16=10+4=14y =10 + \sqrt{10+6} =10 + \sqrt{16} =10 +4 =14, which is not equal to 66.
For x=3x =3, we have y=3+3+6=3+9=3+3=6y =3 + \sqrt{3+6} =3 + \sqrt{9} =3 +3 =6, which is equal to 66.
So, the only solution is x=3x =3.

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