A right angle triangle has sides of lengths (X +5) cm (X - 3) cm and 9cm
What is the value of x?
Can someone please help me answer this maths question ?
回答 (2)
2020-06-09 1:30 am
(x + 5)² + (x - 3)² = 9² (Pythagorean theorem)
x² + 10x + 25 + x² - 6x + 9 = 81
2x² + 4x - 47 = 0
x = [-4 ± √(4² + 4*2*47)] / (2*2)
x = 3.95 or x = -5.95 (rejected for x - 3 < 0)
The answer: x = 3.95
x² + 10x + 25 + x² - 6x + 9 = 81
2x² + 4x - 47 = 0
x = [-4 ± √(4² + 4*2*47)] / (2*2)
x = 3.95 or x = -5.95 (rejected for x - 3 < 0)
The answer: x = 3.95
2020-06-09 1:29 am
Pythagorean Theorem:
(x+5)^2 + (x-3)^2 = 9^2
x^2 + 10x + 25 + x^2 -6x + 9 = 81
2x^2 +4x +34 = 81
2x^2 + 4x - 47 = 0
Quadratic formula
positive solution x = 7/sqrt(2) - 1
(x+5)^2 + (x-3)^2 = 9^2
x^2 + 10x + 25 + x^2 -6x + 9 = 81
2x^2 +4x +34 = 81
2x^2 + 4x - 47 = 0
Quadratic formula
positive solution x = 7/sqrt(2) - 1
收錄日期: 2021-04-18 18:36:24
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