1. 3x² + 12x - 15 = 0
x = <u>-(12) +/- √((12)² - 4(3)(-15))</u>
2(3)
x = <u>-12 +/- √(144 + 180)</u>
6
x = <u>-12 +/- √(324)
</u> 6<u>
</u> x = <u>-12 +/- 18 </u>
6
x = -2 <u>+</u> 3
x = -2 + 3 x = -2 - 3
x = 1 x = -5
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2. 5x² + 11x + 2 = 0
x = <u>-(11) +/- √((11)² - 4(5)(2))</u>
2(5)
x = <u>-11 +/- √(121 - 40)</u>
10
x = <u>-11 +/- √(81)
</u> 10
x = <u>-11 +/- 9</u>
10
x = -1¹/₁₀ <u>+</u> ⁹/₁₀
x = -1¹/₁₀ + ⁹/₁₀ x = -1¹/₁₀ - ⁹/₁₀
x = ¹/₅ x = -2
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3. 2x² - 11x + 14 = 0
x = <u>-(-11) +/- √((-11)² - 4(2)(14))</u>
2(3)
x = <u>11 +/- √(121 - 102)</u>
6
x = <u>11 +/- √(9)</u>
6
x = <u>11 +/- 3</u>
6
x = 1⁵/₆ <u>+</u> ¹/₂
x = 1⁵/₆ + ¹/₂ x = 1⁵/₆ - ¹/₂
x = 2¹/₃ x = 1¹/₃
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4. 2x² - x - 15 = 0
x = <u>-(-1) +/- √((-1)² - 4(2)(-15))</u>
2(2)
x = <u>1 +/- √(1 + 120)</u>
4
x = <u>1 +/- √(121)</u>
4
x = <u>1 +/- 11</u>
4
x = ¹/₄ <u>+</u> 2³/₄
x = ¹/₄ + 2³/₄ x = ¹/₄ - 2³/₄
x = 3 x = 2¹/₂
<u />
Problem
After five years of earning interest at an annual rate of 3%, an investment has earned $950 in interest. To the nearest whole dollar, determine the amount of the initial investment.
Result
The initial investment was $6,333.
Solution
P = I/ i · t
P = 950/ 0.03 · 5
P = 6,333.333
Answer:
The answer is about 32,000.
Step-by-step explanation:
If you multiply 3.2 by 10, for 10 years, you get 32 percent. From there, if you multiply 25,000 by 0.32, you get 8000. If you add 25,000 to 8000, you get about 32,000.
I think that (1/4)x+8 would be your algebraic expression.
