What must be added to make this a perfect square: x(squared) - 7x ?
2015-10-08 1:57 pm
Should we take the coefficient's sign also , that is, (-7/2) squared, or just (7/2) squared?
回答 (3)
2015-10-08 2:55 pm
49/4
2015-10-08 2:52 pm
(-7/2)^2 is the same as (7/2)^2 = 49/4 which must be added and subtracted.
x^2 - 7x = x^2 -7x + (7/2)^2 - (7/2)^2
= (x-7/2)^2 - 49/4
x^2 - 7x = x^2 -7x + (7/2)^2 - (7/2)^2
= (x-7/2)^2 - 49/4
2015-10-08 1:58 pm
x² - 7x
coefficient of x term: -7
divide it in half: -7/2
square it: (-7/2)² = (7/2)²
x² - 7x + (7/2)² = (x - 7/2)²
coefficient of x term: -7
divide it in half: -7/2
square it: (-7/2)² = (7/2)²
x² - 7x + (7/2)² = (x - 7/2)²
收錄日期: 2021-04-21 14:33:34
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