If 2x² + 8y= 121.5 and x² - 8y= 121.5, then x =?

Solution:

The given equations are

2x² + 8y = 121.5

x² - 8y = 121.5

Let us make use of the elimination method

By adding both the equations

2x² + x² + (8y - 8y) = 121.5 + 121.5

By further calculation

3x² = 243

Dividing both sides by 3

x² = 81

Taking square root on both sides

x = √81

x = 9

Therefore, x = 9.

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If 2x² + 8y= 121.5 and x² - 8y= 121.5, then x =?

Summary:

If 2x² + 8y= 121.5 and x² - 8y= 121.5, then x = 9.