Evaluate
\left(4-5a\right)\left(9a+4\right)
Expand
16+16a-45a^{2}
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36a-45a^{2}+16-20a
Apply the distributive property by multiplying each term of 9a+4 by each term of 4-5a.
16a-45a^{2}+16
Combine 36a and -20a to get 16a.
36a-45a^{2}+16-20a
Apply the distributive property by multiplying each term of 9a+4 by each term of 4-5a.
16a-45a^{2}+16
Combine 36a and -20a to get 16a.
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