# Solve the Quadratic Equation X2 - 3(X + 3) = 0; Give Your Answer Correct Two Significant Figures - Mathematics

Sum

Solve the quadratic equation x2 -  3(x + 3) = 0; Give your answer correct two significant figures

#### Solution

x2 -  3(x + 3) = 0

=> x^2 - 3x - 9 = 0

Comparing with ax^2 + by + c we get

:. x = (-b+-sqrt(b^2 - 4ac))/(2a)

=> x = (-(-3)+- sqrt((-3)^2 - 4(1)(-9)))/(2(1))

=> x = (3+- sqrt(9+36))/2

=> x = (3+- sqrt45)/2

=> x = (3+- sqrt(9xx5))/2

=> x = (3+-3sqrt5)/2

=> x = (3+3sqrt5)/2 or x = (3-3sqrt5)/2

=> x  = (3+3xx2.236)/2 or x = (3-3xx2.236)/2

=> x = (3+6.708)/2 or x = (3-6.708)/2

=> x = 9.708/2 or x = (-3.708)/2

=> x = 4.85 or x = -1.85

=> x = 4.9 or x = -1.9

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#### APPEARS IN

Selina Concise Maths Class 10 ICSE