Question

Solve by cross-multiplication method: 3x – 5y = 4; 9x = 2y + 8

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Answer 1

Step-by-step explanation:

3x - 5y - 4 = 0

a¹. b¹. c¹

9x - 2y - 8 = 0

a². b². c²

x = b¹c² - b²c¹ / a¹b² - a²b¹

= -5 × (-8) - (-2) × (-4) / 3 × (-2) - 9 × (-5)

= 40 - 8 / -6 + 45

= 32 / 39

= 0.82

y = c¹a² - c²a¹ / a¹b² - a²b¹

= -4 × 9 - (-8) × 3 / 3 × (-2) - 9 × (-5)

= -36 + 24 / -6 + 45

= -12 / 39

= 0.30

Therefore x = 0.82 & y = 0.30