Identify expression and exponents: Identify the expression inside the brackets and the exponents.The expression inside the brackets is (2j−5k)2, and it is being squared again by the outer exponent of 2.
Square expression inside brackets: Square the expression inside the brackets.To square (2j−5k)2, we multiply the expression by itself: (2j−5k)×(2j−5k).
Use FOIL method to expand: Use the FOIL method (First, Outer, Inner, Last) to expand the expression.(2j−5k)∗(2j−5k)=(2j∗2j)+(2j∗−5k)+(−5k∗2j)+(−5k∗−5k)
Simplify terms from expansion: Simplify the terms from the FOIL expansion.(2j⋅2j)=4j2, (2j⋅(−5k))=−10jk, (−5k⋅2j)=−10jk, (−5k⋅(−5k))=25k2So, (2j−5k)2=4j2−10jk−10jk+25k2
Combine like terms: Combine like terms from the simplified FOIL expansion.−10jk−10jk=−20jkSo, (2j−5k)2=4j2−20jk+25k2
Apply outer exponent: Apply the outer exponent of 2 to the squared expression.[−3(4j2−20jk+25k2)]2 means we need to square −3 and multiply it by the square of the expression (4j2−20jk+25k2).
Square coefficient −3: Square the coefficient −3.(−3)2=9
Square trinomial expression: Square the expression (4j2−20jk+25k2). When squaring a trinomial, each term is squared and the cross-products are doubled. (4j2)2=16j4, (−20jk)2=400j2k2, (25k2)2=625k4
Calculate cross-products: Calculate the cross-products and double them.The cross-products are 2×(4j2×−20jk) and 2×(−20jk×25k2).2×(4j2×−20jk)=−160j3k, 2×(−20jk×25k2)=−1000jk3
Combine squared terms: Combine the squared terms and the doubled cross-products.16j4+(−160j3k)+400j2k2+(−1000jk3)+625k4
Multiply by squared coefficient: Multiply the combined expression by the squared coefficient 9. 9∗(16j4−160j3k+400j2k2−1000jk3+625k4)
Distribute coefficient to terms: Distribute the coefficient 9 to each term in the expression.9×16j4=144j4, 9×(−160j3k)=−1440j3k, 9×400j2k2=3600j2k2, 9×(−1000jk3)=−9000jk3, 9×625k4=5625k4
Combine distributed terms: Combine the distributed terms to get the final expression. 144j4−1440j3k+3600j2k2−9000jk3+5625k4
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