Let x = John's age now
half of what johns age was 4 years ago: (1/2)(x-4)
is equal to one third of what it will be in 5 years time: (1/3)(x+5)
(1/2)(x-4) = (1/3)(x+5)
3(x-4) = 2(x+5)
3x - 12 = 2x + 10
3x^2 - 7x + 12 = 0 ....subtract 12 from both sides
3x^2 - 7x = -12 ....divide both sides by 3 to get x^2 by itself
x^2 - 7/3x = -4
His work is not accurate because he divided the second term by 4 instead of 3.
The equivalent value of the expression is -7
<h3>Modulus of a function</h3>
The modulus of an expression of value is equal to the positive of such function or value.
Given the expression
2(2.5 - |-6|)
Since the value of -6 is a modulus, the expression will become;
2(2.5 - |-6|) = 2(2.5) - 2(6)
2(2.5 - |-6|) = 5 - 12
2(2.5 - |-6|) = -7
Hence the equivalent value of the expression is -7
Learn more on equation here: brainly.com/question/2972832
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