Asked by Destiny Bryant on Apr 28, 2024

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Solve the system by the method of elimination. {x2+y2=5x2−y2=3\left\{ \begin{array} { l } x ^ { 2 } + y ^ { 2 } = 5 \\x ^ { 2 } - y ^ { 2 } = 3\end{array} \right.{x2+y2=5x2y2=3

A) (4,1) ,(−4,1) ( 4,1 ) , ( - 4,1 ) (4,1) ,(4,1)
B) (2,1) ,(−2,1) ( 2,1 ) , ( - 2,1 ) (2,1) ,(2,1)
C) (4,−1) ,(4,1) ,(−4,−1) ,(−4,1) ( 4 , - 1 ) , ( 4,1 ) , ( - 4 , - 1 ) , ( - 4,1 ) (4,1) ,(4,1) ,(4,1) ,(4,1)
D) (2,−1) ,(2,1) ,(−2,−1) ,(−2,1) ( 2 , - 1 ) , ( 2,1 ) , ( - 2 , - 1 ) , ( - 2,1 ) (2,1) ,(2,1) ,(2,1) ,(2,1)
E) no solution exists

Method of Elimination

A technique used in solving systems of equations where one variable is eliminated by adding or subtracting the equations.

System of Equations

A set of two or more equations with the same variables, solved together to find common solutions.

  • Solve systems of equations by the method of elimination.
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Verified Answer

KM
Kimberly MamchurApr 28, 2024
Final Answer :
D
Explanation :
We can use the method of elimination by adding the two equations together. This will eliminate the $y^2$ term:

(x2+y2)+(x2−y2)=5+32x2=8x2=4x=±2\begin{align*}(x^2+y^2) + (x^2-y^2) &= 5+3 \\2x^2 &= 8 \\x^2 &= 4 \\x &= \pm 2 \\\end{align*}(x2+y2)+(x2y2)2x2x2x=5+3=8=4=±2

Now we can substitute this value of $x$ into either of the original equations to find the corresponding value of $y$. Substituting into the first equation gives:

x2+y2=5(2)2+y2=5y2=1y=±1\begin{align*}x^2 + y^2 &= 5 \\(2)^2 + y^2 &= 5 \\y^2 &= 1 \\y &= \pm 1 \\\end{align*}x2+y2(2)2+y2y2y=5=5=1=±1

Therefore, the solution is $(2,1)$, $(-2,1)$, $(2,-1)$, and $(-2,-1)$, which correspond to choice D.