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Match the quadratic equation to its answer. Round to the nearest tenth if necessary.

a. [tex]x = 6.2, -6.2[/tex]
b. [tex]x = 4, -4[/tex]
c. [tex]x = 8, -8[/tex]
d. [tex]x = 1.2, -1.2[/tex]
e. [tex]x = 5, -5[/tex]

1. [tex]2x^2 - 3 = 29[/tex]
2. [tex]-1 - 5x^2 = -321[/tex]
3. [tex]3x^2 = 75[/tex]
4. [tex]8x^2 + 9 = 313[/tex]
5. [tex]32 = 25x^2 - 4[/tex]


Sagot :

Sure, let's solve each quadratic equation step-by-step:

### Equation 1: [tex]\(2x^2 - 3 = 29\)[/tex]

1. Add 3 to both sides:
[tex]\[ 2x^2 - 3 + 3 = 29 + 3 \implies 2x^2 = 32 \][/tex]

2. Divide by 2:
[tex]\[ x^2 = \frac{32}{2} \implies x^2 = 16 \][/tex]

3. Take the square root of both sides:
[tex]\[ x = \pm \sqrt{16} \implies x = \pm 4 \][/tex]

So, the solution is [tex]\(x = 4, -4\)[/tex], which matches with (b).

### Equation 2: [tex]\(-1 - 5x^2 = -321\)[/tex]

1. Add 1 to both sides:
[tex]\[ -1 + 1 - 5x^2 = -321 + 1 \implies -5x^2 = -320 \][/tex]

2. Divide by -5:
[tex]\[ x^2 = \frac{-320}{-5} \implies x^2 = 64 \][/tex]

3. Take the square root of both sides:
[tex]\[ x = \pm \sqrt{64} \implies x = \pm 8 \][/tex]

So, the solution is [tex]\(x = 8, -8\)[/tex], which matches with (c).

### Equation 3: [tex]\(3x^2 = 75\)[/tex]

1. Divide by 3:
[tex]\[ x^2 = \frac{75}{3} \implies x^2 = 25 \][/tex]

2. Take the square root of both sides:
[tex]\[ x = \pm \sqrt{25} \implies x = \pm 5 \][/tex]

So, the solution is [tex]\(x = 5, -5\)[/tex], which matches with (e).

### Equation 4: [tex]\(8x^2 + 9 = 313\)[/tex]

1. Subtract 9 from both sides:
[tex]\[ 8x^2 + 9 - 9 = 313 - 9 \implies 8x^2 = 304 \][/tex]

2. Divide by 8:
[tex]\[ x^2 = \frac{304}{8} \implies x^2 = 38 \][/tex]

3. Take the square root of both sides (and round to the nearest tenth):
[tex]\[ x = \pm \sqrt{38} \approx \pm 6.2 \][/tex]

So, the solution is [tex]\(x \approx 6.2, -6.2\)[/tex], which matches with (a).

### Equation 5: [tex]\(32 = 25x^2 - 4\)[/tex]

1. Add 4 to both sides:
[tex]\[ 32 + 4 = 25x^2 - 4 + 4 \implies 36 = 25x^2 \][/tex]

2. Divide by 25:
[tex]\[ x^2 = \frac{36}{25} \implies x^2 = 1.44 \][/tex]

3. Take the square root of both sides (and round to the nearest tenth):
[tex]\[ x = \pm \sqrt{1.44} \approx \pm 1.2 \][/tex]

So, the solution is [tex]\(x \approx 1.2, -1.2\)[/tex], which matches with (d).

### Summary:
1. [tex]\(2x^2 - 3 = 29\)[/tex] matches with (b): [tex]\(x=4, -4\)[/tex]
2. [tex]\(-1 - 5x^2 = -321\)[/tex] matches with (c): [tex]\(x=8, -8\)[/tex]
3. [tex]\(3x^2 = 75\)[/tex] matches with (e): [tex]\(x=5, -5\)[/tex]
4. [tex]\(8x^2 + 9 = 313\)[/tex] matches with (a): [tex]\(x=6.2, -6.2\)[/tex]
5. [tex]\(32 = 25x^2 - 4\)[/tex] matches with (d): [tex]\(x=1.2, -1.2\)[/tex]