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If a^3 + b^3 = 10 and a + b = 2, then find ab.

 Dec 29, 2020

Best Answer 

 #1
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10=(a3+b3)

    =(a+b)(a2-ab+b2)                  Factor differnce of cubes

    =(a+b)(a2+2ab+b2-3ab)

    =(a+b)((a+b)2-3ab)

    =(2)(22-3ab)

so

5=4-3ab

1=-3ab

ab=-1/3

 Dec 29, 2020
 #1
avatar
+1
Best Answer

10=(a3+b3)

    =(a+b)(a2-ab+b2)                  Factor differnce of cubes

    =(a+b)(a2+2ab+b2-3ab)

    =(a+b)((a+b)2-3ab)

    =(2)(22-3ab)

so

5=4-3ab

1=-3ab

ab=-1/3

Guest Dec 29, 2020

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