Use the formula to expand-8 p x-q y3

We know that (a + b)3 = a3 + 3a2b + 3ab2 + b3 . Comparing nbsp;(px + qy)3 with (a + b)3 , we get: a = px and b = qy Substituting these in the above formula: ( ...

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Byju's Answer

Standard VIII

Mathematics

Algebraic Identities

Use the formu...

Question

Use the formula to expand:

(8) (px + qy)³

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Solution

We know that (a + b)³ = a³ + 3a²b + 3ab² + b³ .
Comparing (px + qy)³ with (a + b)³ , we get:
a = px and b = qy
Substituting these in the above formula:
(px + qy)³ = (px)³ + 3 × (px)² × qy + 3 × px × (qy)² + (qy)³
= p³x³ + 3p²qx²y + 3pq²xy² + q³y³

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Use the formula to expand: (8) (px + qy)3

We know that (a + b)3 = a3 + 3a2b + 3ab2 + b3 . Comparing (px + qy)3 with (a + b)3 , we get: a = px and b = qy Substituting these in the above formula: (px + qy)3 = (px)3 + 3 × (px)2 × qy + 3 × px × (qy)2 + (qy)3 = p3x3 + 3p2qx2y + 3pq2xy2 + q3y3

Use the formula to expand:

(8) (px + qy)³

We know that (a + b)³ = a³ + 3a²b + 3ab² + b³ .
Comparing (px + qy)³ with (a + b)³ , we get:
a = px and b = qy
Substituting these in the above formula:
(px + qy)³ = (px)³ + 3 × (px)² × qy + 3 × px × (qy)² + (qy)³
= p³x³ + 3p²qx²y + 3pq²xy² + q³y³