Solve the system by the substitution method.
-$$x ^ { 2 } + y ^ { 2 } = 49$$
$y - x = 7$
A) $\{ ( 0,7 ) , ( 7,0 ) \}$
B) $\{ ( 0 , - 7 ) , ( - 7,0 ) \}$
C) $\{ ( 0,7 ) , ( - 7,0 ) \}$
D) $\{ ( 0 , - 7 ) , ( 7,0 ) \}$

Question

Quizplus · Accepted Answer

From the second equation, $y = x + 7$. Substituting $y$ in the first equation gives $x^2 + (x+7)^2 = 49$. Solving this equation yields $x = 0$ and $x = -7$. Substituting these values back into $y = x + 7$ gives the pairs $(0, 7)$ and $(-7, 0)$.

Solve the System by the Substitution Method x2+y2=49x ^ { 2 } + y ^ { 2 } = 49x2+y2=49

Solve the System by the Substitution Method $x ^ { 2 } + y ^ { 2 } = 49$