What is an approximate x-value for the equation y = - 3x2 + 16 when y = 8?

Question

Mathematics

Nigel

17 February, 23:33

What is an approximate x-value for the equation y = - 3x2 + 16 when y = 8?

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Answers (1)

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Marco Beasley · Answer 1

y = - 3x² + 16

y = 8

-3x² + 16 = 8 | - 16

-3x² = - 8 | : (-3)

x² = 8/3

x² = 4 · 2/3

x = √ (4 · 2/3)

x = 2√ (2/3)

√ (2/3) = 0,81649 ... ≈ 0,82

x ≈ 2 · 0,82

x ≈ 1,64