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precision solve each equation. if exact roots cannot be found, state th…

Question

precision solve each equation. if exact roots cannot be found, state the consecutive integers between which the roots are located. 4. $x^2 + 8x = 0$ 5 $x^2 - 3x - 18 = 0$ 6. $4x - x^2 + 8 = 0$ 7. $-12 - 5x + 3x^2 = 0$ 8. $x^2 - 6x + 4 = -8$ 9. $9 - x^2 = 12$ 10. $5x^2 + 10x - 4 = -6$ 11. $x^2 - 20 = 2 + x$

Explanation:

Response
Problem 4: \( x^2 + 8x = 0 \)

Step1: Factor out \( x \)

\( x(x + 8) = 0 \)

Step2: Apply zero - product property

If \( ab = 0 \), then either \( a = 0 \) or \( b = 0 \). So \( x = 0 \) or \( x+8 = 0 \)

Step3: Solve for \( x \)

For \( x + 8=0 \), we get \( x=-8 \)

Step1: Factor the quadratic

We need two numbers that multiply to \( - 18\) and add up to \( - 3\). The numbers are \( - 6\) and \( 3\). So \( x^2-3x - 18=(x - 6)(x+3)=0 \)

Step2: Apply zero - product property

\( x - 6=0 \) or \( x + 3=0 \)

Step3: Solve for \( x \)

For \( x - 6=0 \), \( x = 6 \); for \( x+3 = 0 \), \( x=-3 \)

Step1: Rewrite in standard form

\( -x^2+4x + 8=0 \), multiply both sides by \( - 1\) to get \( x^2-4x - 8=0 \)

Step2: Use quadratic formula \( x=\frac{-b\pm\sqrt{b^2 - 4ac}}{2a}\), where \( a = 1\), \( b=-4 \), \( c=-8 \)

First, calculate the discriminant \( \Delta=b^2-4ac=(-4)^2-4\times1\times(-8)=16 + 32=48 \)

Step3: Find the roots

\( x=\frac{4\pm\sqrt{48}}{2}=\frac{4\pm4\sqrt{3}}{2}=2\pm2\sqrt{3}\)
\( \sqrt{3}\approx1.732 \), so \( 2 + 2\sqrt{3}\approx2 + 3.464 = 5.464\) and \( 2-2\sqrt{3}\approx2-3.464=-1.464 \)
The root \( 2 - 2\sqrt{3}\) is between \( - 2\) and \( - 1\), and the root \( 2 + 2\sqrt{3}\) is between \( 5\) and \( 6\)

Answer:

The solutions are \( x = 0 \) and \( x=-8 \)

Problem 5: \( x^2-3x - 18=0 \)