You can put this solution on YOUR website! Expand the expression
(2z+5k)^4
using the binomial theorem and pascal's triangle.
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The 4th power coefficients of Pascal's triangl are
1 4 6 4 1
For exponents, 2, 3 & 4 they're 11^2, 11^3 and 11^4
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--> (2z)^2 + 4*(2z)^3*5k + 6*(2z)^2*(5k)^2 + 4*2z*(5k)^3 + (5k)^4
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You can check you answer against that when doing the binomial expansion.
