Solve the equation below : 7 – 9x – 15 + 12x
2 answers:
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Answer:
Step-by-step explanation:
Hypotenuse² =base² + altitude²
(3x + 4)² = (2x + 1)² + (3x)²
{Use (a+b)² = a² + 2ab + b²}
(3x)² + 2*3x+4 + 4² = (2x)² + 2*2x*1 + 1² + 9x²
9x² + 24x + 16 = 4x² + 4x + 1 + 9x²
9x² + 24x + 16 = 13x² + 4x + 1
0 = 13x² + 4x + 1 - 9x² - 24x - 16
13x² - 9x² + 4x - 24x +1 - 16 = 0
4x² - 20x - 15 = 0
a = 4 ; b =-20 ; c = -15
D = b² - 4ac = (-20)² - 4*4*(-15) = 400 + 240 = 640
√D = √640 = 25.30
x = 5 .66 ; x = -0.66
Ignore x = -0.66 as length of a side cannot be negative
Answer : x = 5.66