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Solve for \( x \) : (Where applicable, leave your answers as indicated in brackets.) \( \begin{array}{ll}\text { (1) } x^{2}-2 x=3 & \text { (2) } 3 x^{2}-27=0 \\ \text { (3) } x^{2}-3 x-2=0 \text { (surd form) } & \text { (4) }-x^{2}-x=-5 \text { (surd form) } \\ \text { (5) }-x^{2}-5 x=2 \text { (surd form) } & \text { (6) } x^{2}-11 x=-30 \\ \text { (7) } x^{2}-12=0 \text { (surd form) } & \text { (8) }-2 x^{2}+6 x=0\end{array} \)

Ask by Spencer Horton. in South Africa
Feb 03,2025

Real Tutor Solution

Tutor-Verified Answer

Answer

Here are the solutions for each equation: 1. \( x = 3 \) and \( x = -1 \) 2. \( x = 3 \) and \( x = -3 \) 3. \( x = \dfrac{3 \pm \sqrt{17}}{2} \) 4. \( x = \dfrac{-1 \pm \sqrt{21}}{2} \) 5. \( x = \dfrac{-5 \pm \sqrt{17}}{2} \) 6. \( x = 5 \) and \( x = 6 \) 7. \( x = \pm 2\sqrt{3} \) 8. \( x = 0 \) and \( x = 3 \)

Solution

Let's solve each of the given equations step by step. --- **(1) \( x^{2} - 2x = 3 \)** Rewrite the equation: \[ x^{2} - 2x - 3 = 0 \] Factor or use the quadratic formula: \[ x = \frac{2 \pm \sqrt{(−2)^2 - 4(1)(−3)}}{2(1)} = \frac{2 \pm \sqrt{4 + 12}}{2} = \frac{2 \pm \sqrt{16}}{2} \] \[ x = \frac{2 \pm 4}{2} \Rightarrow x = 3 \text{ or } x = -1 \] **Solution:** \( x = 3 \) and \( x = -1 \) --- **(2) \( 3x^{2} - 27 = 0 \)** Simplify the equation: \[ 3x^{2} = 27 \Rightarrow x^{2} = 9 \] \[ x = \pm 3 \] **Solution:** \( x = 3 \) and \( x = -3 \) --- **(3) \( x^{2} - 3x - 2 = 0 \) (surd form)** Use the quadratic formula: \[ x = \frac{3 \pm \sqrt{(-3)^2 - 4(1)(-2)}}{2(1)} = \frac{3 \pm \sqrt{9 + 8}}{2} = \frac{3 \pm \sqrt{17}}{2} \] **Solution:** \( x = \dfrac{3 \pm \sqrt{17}}{2} \) --- **(4) \( -x^{2} - x = -5 \) (surd form)** Rewrite the equation: \[ -x^{2} - x + 5 = 0 \Rightarrow x^{2} + x - 5 = 0 \] Use the quadratic formula: \[ x = \frac{-1 \pm \sqrt{1^2 - 4(1)(-5)}}{2(1)} = \frac{-1 \pm \sqrt{1 + 20}}{2} = \frac{-1 \pm \sqrt{21}}{2} \] **Solution:** \( x = \dfrac{-1 \pm \sqrt{21}}{2} \) --- **(5) \( -x^{2} - 5x = 2 \) (surd form)** Rewrite the equation: \[ -x^{2} - 5x - 2 = 0 \Rightarrow x^{2} + 5x + 2 = 0 \] Use the quadratic formula: \[ x = \frac{-5 \pm \sqrt{5^2 - 4(1)(2)}}{2(1)} = \frac{-5 \pm \sqrt{25 - 8}}{2} = \frac{-5 \pm \sqrt{17}}{2} \] **Solution:** \( x = \dfrac{-5 \pm \sqrt{17}}{2} \) --- **(6) \( x^{2} - 11x = -30 \)** Rewrite the equation: \[ x^{2} - 11x + 30 = 0 \] Factor the quadratic: \[ (x - 5)(x - 6) = 0 \] \[ x = 5 \text{ or } x = 6 \] **Solution:** \( x = 5 \) and \( x = 6 \) --- **(7) \( x^{2} - 12 = 0 \) (surd form)** Solve for \( x \): \[ x^{2} = 12 \Rightarrow x = \pm \sqrt{12} = \pm 2\sqrt{3} \] **Solution:** \( x = \pm 2\sqrt{3} \) --- **(8) \( -2x^{2} + 6x = 0 \)** Factor the equation: \[ -2x(x - 3) = 0 \] \[ x = 0 \text{ or } x = 3 \] **Solution:** \( x = 0 \) and \( x = 3 \) --- **Summary of Solutions:** 1. \( x = 3 \), \( x = -1 \) 2. \( x = 3 \), \( x = -3 \) 3. \( x = \dfrac{3 \pm \sqrt{17}}{2} \) 4. \( x = \dfrac{-1 \pm \sqrt{21}}{2} \) 5. \( x = \dfrac{-5 \pm \sqrt{17}}{2} \) 6. \( x = 5 \), \( x = 6 \) 7. \( x = \pm 2\sqrt{3} \) 8. \( x = 0 \), \( x = 3 \)

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Let's solve each equation one by one: **(1)** \( x^{2}-2x=3 \) Rearranging gives us \( x^{2}-2x-3=0 \). Factoring, we have \( (x-3)(x+1)=0 \). Thus, \( x=3 \) or \( x=-1 \). --- **(2)** \( 3x^{2}-27=0 \) Dividing by 3, we get \( x^{2}-9=0 \). Factoring gives \( (x-3)(x+3)=0 \), so \( x=3 \) or \( x=-3 \). --- **(3)** \( x^{2}-3x-2=0 \) Using the quadratic formula \( x=\frac{-b\pm\sqrt{b^{2}-4ac}}{2a} \), we get \( x=\frac{3\pm\sqrt{(3)^{2}-4(1)(-2)}}{2(1)} = \frac{3\pm\sqrt{17}}{2} \). --- **(4)** \( -x^{2}-x=-5 \) Rearranging gives \( x^{2}+x-5=0 \). Using the quadratic formula: \( x=\frac{-1\pm\sqrt{1^{2}-4(1)(-5)}}{2(1)}= \frac{-1\pm\sqrt{21}}{2} \). --- **(5)** \( -x^{2}-5x=2 \) Rearranging gives \( x^{2}+5x+2=0 \). Using the quadratic formula: \( x=\frac{-5\pm\sqrt{5^{2}-4(1)(2)}}{2(1)}= \frac{-5\pm\sqrt{17}}{2} \). --- **(6)** \( x^{2}-11x=-30 \) Rearranging gives \( x^{2}-11x+30=0 \). Factoring gives \( (x-6)(x-5)=0 \), so \( x=6 \) or \( x=5 \). --- **(7)** \( x^{2}-12=0 \) This can be rearranged to \( x^{2}=12 \) leading to \( x=\pm 2\sqrt{3} \). --- **(8)** \( -2x^{2}+6x=0 \) Factoring out \(-2x\) gives \( -2x(x-3)=0 \), hence \( x=0 \) or \( x=3 \). --- In summary, the answers for the equations are: 1. \( x = 3, -1 \) 2. \( x = 3, -3 \) 3. \( x = \frac{3 \pm \sqrt{17}}{2} \) 4. \( x = \frac{-1 \pm \sqrt{21}}{2} \) 5. \( x = \frac{-5 \pm \sqrt{17}}{2} \) 6. \( x = 5, 6 \) 7. \( x = \pm 2\sqrt{3} \) 8. \( x = 0, 3 \)

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