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[tex]{\huge{\underline{\underline{\boxed{\blue{\mathscr{ Answer }}}}}}}[/tex]
To find (I + A)³ - 7A when A² = A, let's use the binomial expansion formula for (I + A)³:
(I + A)³ = I³ + 3I²A + 3IA² + A³
Since A² = A, we can simplify further:
(I + A)³ = I + 3IA + 3IA + A³
Now, subtract 7A:
(I + 3IA + 3IA + A³) - 7A = I + 6IA + A³ - 7A
Since A² = A, we can replace A³ with A in the expression:
I + 6IA + A - 7A
Now, combine like terms:
I + A - A = I
So, (I + A)³ - 7A is equal to I, which corresponds to option (d) "I."
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[tex]{\huge{\underline{\underline{\boxed{\blue{\mathscr{ Answer }}}}}}}[/tex]
To find (I + A)³ - 7A when A² = A, let's use the binomial expansion formula for (I + A)³:
(I + A)³ = I³ + 3I²A + 3IA² + A³
Since A² = A, we can simplify further:
(I + A)³ = I + 3IA + 3IA + A³
Now, subtract 7A:
(I + 3IA + 3IA + A³) - 7A = I + 6IA + A³ - 7A
Since A² = A, we can replace A³ with A in the expression:
I + 6IA + A - 7A
Now, combine like terms:
I + A - A = I
So, (I + A)³ - 7A is equal to I, which corresponds to option (d) "I."