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12. For which values of x and y is the value of

the expression below less than 30?
2x² - p³
A. x = 9 and y=5
B. x = 4 andy=1
C. x = 7 and y=4
D. x=5 and y=3

User Madaline
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1 Answer

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Answer: The expression is 2x² - p³.

To find the values of x and y for which the expression is less than 30, we need to substitute the given values of x and y into the expression and then solve for p.

Let's consider each option:

A. x = 9 and y = 5

Expression = 2(9)² - p³ = 2(81) - p³ = 162 - p³

B. x = 4 and y = 1

Expression = 2(4)² - p³ = 2(16) - p³ = 32 - p³

C. x = 7 and y = 4

Expression = 2(7)² - p³ = 2(49) - p³ = 98 - p³

D. x = 5 and y = 3

Expression = 2(5)² - p³ = 2(25) - p³ = 50 - p³

We need the value of the expression to be less than 30, so we have the inequality:

Expression < 30

Now, let's compare each expression to 30:

A. 162 - p³ < 30

B. 32 - p³ < 30

C. 98 - p³ < 30

D. 50 - p³ < 30

To find the values of p that satisfy each inequality, we need to rearrange them and solve for p:

A. - p³ < 30 - 162

p³ < -132

p³ > 132

Since p³ is positive, we have: p > (132)^(1/3)

B. - p³ < 30 - 32

p³ < -2

p³ > 2

Since p³ is positive, we have: p > (2)^(1/3)

C. - p³ < 30 - 98

p³ < -68

p³ > 68

Since p³ is positive, we have: p > (68)^(1/3)

D. - p³ < 30 - 50

p³ < -20

p³ > 20

Since p³ is positive, we have: p > (20)^(1/3)

Now, let's find the values of (132)^(1/3), (2)^(1/3), (68)^(1/3), and (20)^(1/3):

(132)^(1/3) ≈ 5.282

(2)^(1/3) ≈ 1.260

(68)^(1/3) ≈ 4.132

(20)^(1/3) ≈ 2.714

So, the values of p satisfying each inequality are:

A. p > 5.282

B. p > 1.260

C. p > 4.132

D. p > 2.714

To summarize, for the expression 2x² - p³ to be less than 30, the value of p must be greater than 5.282, 1.260, 4.132, and 2.714. None of the given options satisfy all of these conditions, so none of the provided options are correct.

User Berriel
by
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