If a-b=4 and ab=21 find the value of a cube- b cube
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is it correct? pls .match with answer
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a³-b³ = (a-b)(a²+b²+ab)
= (a-b){(a-b)²+2ab +ab}
= (a-b){(a-b)²+3ab}
using the relation,
a²+b² = (a-b)²+2ab
Now, just substitute the values given in the question and you will get the answer.
a³ - b³= 4×{4²+3×21} = 4×{16+ 63}= 4×79
=316
I hope you find it helpful. All the best.
Please mark it as brainliest if you find it helpful.
= (a-b){(a-b)²+2ab +ab}
= (a-b){(a-b)²+3ab}
using the relation,
a²+b² = (a-b)²+2ab
Now, just substitute the values given in the question and you will get the answer.
a³ - b³= 4×{4²+3×21} = 4×{16+ 63}= 4×79
=316
I hope you find it helpful. All the best.
Please mark it as brainliest if you find it helpful.
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