<span>This is a quadratic equation . We order to equate to zero
</span>2x²<span> – 7 = 9
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2x² - 7-9 = 0
2x² - 16 = 0
This equation is a binomial
2* (x² - 8) = 0
<span>We choose the simplest method . The equation with practice it can be calculated in the memory
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The product is equal to 0 if one of the factors is zero
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2≠0 ∨ x² - 8 = 0
x² = √8
x = √8 ∨ x= - √8
Answer : x = √8 ∨ x = -√8
The first thing we must do for this case is to define a variable.
We have then:
n: unknown number.
We write the algebraic expression:
13 - 4n
For n = 3 we have:
13 - 4 (3) = 13 - 12 = 1
Answer:
An expression that represents this phrase is:
13 - 4n
its value if n = 3 is:
1
3 3/6 is the same as 3 1/2, so 23 take 3 is 20. 20 take 1/2 is 19 1/2.
The answer to the question in the photo is 21