QQuestion
Solve the quadratic equation (x − 2)² − 5x − 3 = 0 and give your answer correct to 3 significant figures.
ICSEClass XMathematicsQuadratic Equations04 Mark2026 Moderate
✓Answer
⇒ (x − 2)2 − 5x − 3 = 0
⇒ x2 – 4x + 4 − 5x − 3 = 0
⇒ x2 – 9x + 1 = 0
Comparing x2 – 9x + 1 = 0 with ax2 + bx + c = 0 , we get :
a = 1, b = -9 and c = 1
\mathrm{x}=\frac{-\mathrm{b}\pm\sqrt{\mathrm{b}^2-4\mathrm{ac}}}{2\mathrm{a}}⇒ \mathrm{x}=\frac{9\pm\sqrt{77}}{2}
⇒ \mathrm{x}=\frac{9+8.775}{2} or \mathrm{x}=\frac{9-8.775}{2}
⇒ x = 8.8875 or x = 0.1125
Correct to 3 significant figures, x = 8.89 or x = 0.113.
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