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.
Learn more about Equations here:
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Answer:
176
Step-by-step explanation:
every 11 mm in the drawing equals 4m.
every 1 mm in the drawing equals 4/11 m
Actual size of school yard = 484*4/11 = 176m
4x + y = 54
8x + 2y = 104
8x + 8y - (8x + 2y) = 240 - 104
6y = 136
y=22 2/3
4x+ 22 2/3 = 54
4x= 31 1/3
x= 7 5/6
(5,28) it's the correct answer
