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Zorluk: KolayNonlinear Systems of Equations

A system of equations is shown below.

y=x22xy = x^2 - 2x
y=3y = 3

If (x,y)(x, y) is a solution to the system of equations and x>0x > 0, what is the value of x+yx + y?

  1. A
    2
  2. B
    3
  3. 6Cevap
  4. D
    4

Cevap

6
To solve the system of equations, substitute the expression for yy from the second equation into the first equation: 3=x22x3 = x^2 - 2x. Subtracting 3 from both sides results in the quadratic equation x22x3=0x^2 - 2x - 3 = 0. Factoring the quadratic yields (x3)(x+1)=0(x - 3)(x + 1) = 0, which gives the possible values of xx as 33 and 1-1. Since the problem specifies that x>0x > 0, the value of xx is 3. Given that y=3y = 3, the value of x+yx + y is 3+3=63 + 3 = 6.

Adım Adım Çözüm

1
Substitute the value of yy from the second equation into the first equation.
3=x22x3 = x^2 - 2x
Since both equations are equal to yy, their right-hand sides must be equal to each other.
2
Rearrange the equation to set it equal to zero.
x22x3=0x^2 - 2x - 3 = 0
This puts the equation into standard quadratic form so that it can be factored.
3
Factor the quadratic equation.
(x3)(x+1)=0(x - 3)(x + 1) = 0
Finding factors of -3 that add up to -2 helps isolate the solutions for xx.
4
Find the solutions for xx and apply the given constraint.
x=3x = 3 (since x>0x > 0)
The factors give x=3x = 3 and x=1x = -1. The constraint x>0x > 0 excludes x=1x = -1.
5
Calculate the value of x+yx + y.
3+3=63 + 3 = 6
Substitute the value of x=3x = 3 and the given value of y=3y = 3 to find the final sum.

Anahtar Kavram

Solving nonlinear systems of equations using substitution and solving quadratic equations by factoring.
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