diketahui x1 dan y1 memenuhi sistem persamaan 4x+7y=5 dan 5x-2y=17 , nilai x1^2+yi^2= ...

Kelas 8 Matematika
Bab SPLDV

4x + 7y = 5 → dikali 5 → 20x + 35y = 25
5x - 2y = 17 → dikali 4 → 20x - 8y = 68

20x + 35y = 25
20x - 8y = 68
---------------------- -
 43y = -43
y = -1

4x + 7y = 5
4x + 7 . (-1) = 5
4x = 5 + 7
x = 12/4
x = 3

x² + y²
= 3² + (-1)²
= 9 + 1
= 10