Mike D. answered • 06/05/21
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number x
number squared x2
3 times number squared 3x2
twice the number 2x
3 times number squared decreased by twice the number
3x2 - 2x = 5
3x2 - 2x - 5 = 0
You can factorise this or use the quadratic formula to find x
Mike D.
3x^2 - 2x - 5 = 0. a = 3, b = -2, c = -5. Find two whole numbers p,q (they might be positive or negative), so that p+q = b, p x q = ac. So p+q = -2, p x q = -15. You can choose p = -5, q = + 3. Then write two fractions p/a and q/a so -5/3 and 3/3. If the numerator is > 1 try and simplify. -5/3 you cannot, 3/3 simplifies to 1/1. -5/3 gives a factor (3x-5) 1/1 gives factor x + 1 . so (3x-5) (x+1) = 0, so 3x-5 = 0 so x = 5/3 or x+1 = 0 giving x = -1.
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06/06/21
Lia M.
I'm not sure what number can add to 2 and multiply to 506/06/21