Mathematics: 2x2 - 4x –9 = 0 Completing the swuare

2x2 - 4x –9 = 0 Completing the swuare

Ответ:

rosieposie27

09.02.2022

Step-by-step explanation:

$(a-b)^2=a^2-2ab+b^2\\\\2x^2-4x-9=0\qquad|\text{add 9 to both sides}\\\\2x^2-4x-9+9=0+9\\\\2x^2-4x=9\qquad|\text{divide both sides by 2}\\\\\dfrac{2x^2}{2}-\dfrac{4x}{2}=\dfrac{9}{2}\\\\x^2-2x=4.5\\\\x^2-2\cdot x\cdot1=4.5\qquad|\text{add}\ 1^2\ \text{to both sides}\\\\x^2-2\cdot x\cdot1+1^2=4.5+1^2\\\\(x-1)^2=5.5\iff x-1=\pm\sqrt{5.5}\qquad|\text{add 1 to both sides}\\\\x=1-\sqrt{5.5}\ \vee\ x=1+\sqrt{5.5}$

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Ответ:

paovue48

18.05.2022

Mathematics

8/18=4/9

Step-by-step explanation:

since it there is 1/6 for red marbles and 5/18 for blue marbles it works because it is 8*9=72 for the denominator and 4*3=12 so it is 12/72=1/6 and for blue it is 5/18 because it is 5*4=20 and 20/72=10/36=5/18 so it is 1/6+5/18=8/18=4/9

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2x2 - 4x –9 = 0
Completing the swuare

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