Solve algebraically y=x^2 + 2x y=3x+20
2 answers:
Answer:
x = 5 and y = 35
OR
x = -4 and y = 8.
Step-by-step explanation:
Equate the right-hand side of the two equations:
x² + 2 x = y = 3 x + 20.
x² + 2 x - 3 x - 20 = 0.
x² - x - 20 = 0.
Quadratic discriminant
Δ = b² - 4 a · c
= (-1)² - 4 × 1 × (-20)
= 81.
There are two roots:
x₁ = (-b + ) / (2 a)
= (- (-1) + ) / (2 × 1)
= (1 + 9) / 2
= 10 / 2
= 5
and
x₂ = (-b - ) / (2 a)
= (1 - 9) / 2
= -4.
Find the value of y in both case.
y₁ = 3 × 5 + 20 = 35.
y₂ = 3 × (-4) + 20 = 8.
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Answer:
0.0032
The complete question as seen in other website:
There are 111 students in a nutrition class. The instructor must choose two students at random Students in a Nutrition Class Nutrition majors Academic Year Freshmen non-Nutrition majors 17 18 Sophomores Juniors 13 Seniors 18 Copy Data. What is the probability that a senior Nutrition major and then a junior Nutrition major are chosen at random? Express your answer as a fraction or a decimal number rounded to four decimal places.
Step-by-step explanation:
Total number of in a nutrition class = 111 students
To determine the probability that the two students chosen at random is a junior non-Nutrition major and then a sophomore Nutrition major, we would find the probability of each of them.
Let the probability of choosing a junior non-Nutrition major = Pr (j non-N)
Pr (j non-N) = (number of junior non-Nutrition major)/(total number students in nutrition class)
There are 13 number of junior non-Nutrition major
Pr (j non-N) = 13/111
Let the probability of choosing a sophomore Nutrition major = Pr (S N-major)
Pr (S N-major)= (number of sophomore Nutrition major)/(total number students in nutrition class)
There are 3 number of sophomore Nutrition major
Pr (S N-major) = 3/111
The probability that the two students chosen at random is a junior non-Nutrition major and then a sophomore Nutrition major = 13/111 × 3/111
= 39/12321
= 0.0032
