To verify if the cube of x is larger than the cube of y,
we need to determine the values of x and y, therefore, we'll have to solve the
system.
We'll use substitution method. We'll re-write the
first equation, isolating y to the left side:
-y = -4x -
5
y = 4x + 5
We'll re-write
the 2nd equation in terms of x:
2(x-1) = 3(4x + 5 +
1)
We'll remove the
brackets:
2x - 2 = 12x +
18
We'll isolate the terms in x to the left
side:
2x - 12x = 18 + 2
-10x =
20
x = -2
We'll determine
y:
y = 4*(-2) + 5
y = -8 +
5
y = -3
We'll raise to cube
the values of x and y:
`x^3 =
(-2)^3`
`x^3 = -8`
`y^3 =
(-3)^3`
`y^3 =
-27`
We notice that -8 > -27,
therefore the inequality `x^3 > y^3` is
verified.
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