Recall geometric mean. Let g be the geometric mean, so the geometric mean of a1, a2, a3 ... an is equal to
g = nth root of (a1 * a2 * ... * an)
Applying this to the problem, we have only two terms involved, which is 2x and 19x-2, thus n = 2. And g is given, which is 7x-2. Substituting,
7x-2 = squareroot (2x * (19x-2))
7x - 2 = squareroot (38x^2 - 4x)
Square both sides:
49x^2 - 28x + 4 = 38x^2 - 4x
49x^2 - 38x^2 - 28x + 4x + 4 = 0
11x^2 - 24x + 4 = 0
x = ?
Now factor this and solve for x. Note that you'll have 2 roots for this, but only 1 will satisfy the given equation above (one of them is extraneous).
Hope this helps~ `u`
math . please help me to answer this i really don't know what is the answer I need the answer later i have 2 more hours to finish this. please help me
Find the value of x if the geometric mean of 2x and 19x-2 is 7x-2
2 answers
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2 answers