- If 2x2 + 8y = 121.5 and x2 - 8y = 121.5, then x = 9 6.36 16 7

1 answer:

4 0

Step-by-step explanation:

2x² + 8y = 121.5

x² - 8y = 121.5

Add the equations together to eliminate the y terms.

3x² = 243

x² = 81

x = 9

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Answer:

$\displaystyle \frac{7}{24}$

General Formulas and Concepts:

Algebra I

Calculus

[Area] Limits of Riemann's Sums - Integrals

Integration Rule [Reverse Power Rule]: $\displaystyle \int {x^n} \, dx = \frac{x^{n + 1}}{n + 1} + C$

Integration Rule [Fundamental Theorem of Calculus 1]: $\displaystyle \int\limits^b_a {f(x)} \, dx = F(b) - F(a)$

Step-by-step explanation:

Step 1: Define

$\displaystyle f(x) = \frac{1}{x^4} \\ \ [1, 2]$

Step 2: Find Area

[Integral] Set up area: $\displaystyle \int\limits^2_1 {\frac{1}{x^4}} \, dx$
[Integral] Rewrite: $\displaystyle \int\limits^2_1 {x^{-4}} \, dx$
[Integral] Reverse Power Rule: $\displaystyle \frac{-1}{3x^3} \bigg| \limits^2_1$
[Area] Fundamental Theorem of Calculus: $\displaystyle \frac{7}{24}$