Question

Nilai dari =...
A. 12
B. 14
C. 15
D. 18
E. 28

Answer 1

1/(4x) + 7/(2y) = 5/4 → Dikali 28xy
1/(2x) - 3/y = -5/14 → Dikali 14xy

Jadi,
7y + 98x = 35xy
7y - 42x = - 5xy
−−−−−−−−−−−−− −
140x = 40xy
7 = 2y
y = 7/2

7y + 98x = 35xy
y + 7x = 5xy
(7/2) + 7x = 5(7/2)x
7 + 14x = 35x
7x = 7
x = 1

x² + y² = ....?
x² + y² = (1)² + (7/2)²
x² + y² = + 49/4
x² + y² = 4/4 + 49/4
x² + y² = 53/4