The possible numbers that Melody could have picked are -4 and 4.
The operation that prevents us from knowing with 100% certainty the number Melody had picked is multiplication which is implied by the phrase "double the number".
Given, Let x be the number Melody had chosen.
Thus, tripling the number will give 3x, and
squaring this will result to (3x)² which is equals to 9x².
Dividing the square of the number by 2 and subtracting 30 from its quotient will give 42:
9x²/2 ₋ 30 = 42
9x²/2 = 42 ₊ 30
9x²/2 = 72
9x² = 72 × 2
9x² = 144
x² = 144/9
x² = 16
x = ±√16
x = ±4
x = ₊4 or x = 4
hence melody could have picked ₊4 or ₋4 numbers.
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Answer:
-4 and -3.
Step-by-step explanation:
Let the numbers be x and x+1.
From the given information:
x^2 + (x + 1)^2 + x = 21
x^2 + x^2 + 2x + 1 + x - 21 = 0
2x^2 + 3x - 20 = 0
(2x - 5 )(x + 4 ) = 0
x = 5/2 or -4 We ignore 5/2 as its not an interger
So the required integers are -4 and -3.
Step-by-step explanation:
- you just substitute (-2) into the x values of the above function

Answer:
15) choice 1
16) choice 4, 72 degrees
17) choice 3) translation
18) choice 3, never
19) choice 3) 2
20) choice 3
21) acute triangle, at least one angle less than 90 degrees
Step-by-step explanation: