Answer: D
Step-by-step explanation:
(3 + 2i) (3-2i) = 13
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 />
In order to solve 5 + y = 7 you have to find the value of (y). In this case you could reverse do problem and do 7 - 5 to get the value of y. 7 - 5 = 2, which means y is equal to 2.
Answer:
4
Step-by-step explanation:
the third angle of the inner triangle is defined by using the rule that the sum of all angles in a triangle must be 180 degrees. let's call this angle a
180 = 48 + 16x + a
132 - 16x = a
and then we know that both angles, 28x and a together must also be 180, as they are complementing each other to cover the whole top of the base line.
so,
28x + 132 - 16x = 180
12x = 48
x = 4