If x=3−4y, then (x 3 +64y 3 +36xy) is equal to: - Quantitative Aptitude MCQ Competitive Exam 2026 | ExamTest.live

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If x=3-4y, then (x 3 +64y 3 +36xy) is equal to:

Solution & Step-by-step Explanation

Given: x=3-4y⟹x+4y=3 We need to evaluate the expression x 3 +64y 3 +36xy. We know the identity: (a+b) 3 =a 3 +b 3 +3ab(a+b) Let a=x and b=4y. (x+4y) 3 =x 3 +(4y) 3 +3(x)(4y)(x+4y) (x+4y) 3 =x 3 +64y 3 +12xy(x+4y) Substitute x+4y=3 into the identity: (3) 3 =x 3 +64y 3 +12xy(3) 27=x 3 +64y 3 +36xy Therefore, the value of the given expression is 27.

Try it yourself before checking the explanation above.

If x=3-4y, then (x 3 +64y 3 +36xy) is equal to:

27(1 + 3xy)

9(3 + 5xy)

27(1 + xy)

27

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