x^2+y^2=169, x+y+17?

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x^2+y^2=169, x+y+17?

Solve the system using the substitution method.

2007-12-02 10:39:51 · 2 answers · asked by malibu0108 1 in Science & Mathematics ➔ Mathematics

2 answers

{x^2+y^2=169
{x+y=17

=>{x=17-y
{(17-y)^2+y^2=169

=>{x=17-y
{289-34y+y^2+y^2=169

=>{x=17-y
{2y^2-34y+120=0

=>{x=17-y
{y=5 or y=12

*For y=5, x=12
*For y=12, x=5

2007-12-02 10:45:25 · answer #1 · answered by coucou_bambie 2 · 0⤊ 0⤋

x^2+y^2=169
x+y=17

x=17-y

(17-y)^2+y^2=169
289-34y+y^2+y^2=169
120-34y+2y^2=0

2y^2-34y+120=0

2(y^2-17y+60)=0

2(y-5)(y-12)=0
y=5,12

x=17-y
x=12,5

2007-12-02 10:47:14 · answer #2 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋