Question

solve (4x+5)(4x-1)by using identities
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Answer 1

16x²-16x-5

$(ax+b)(cx+d)=acx^2+(ac+bd)x+bd$ → identity

Here a=4 b=5 c=4 d=-1

Calculation

→ $16x^2+(-4+20)x+(-5)$

→ $16x^2-16x-5$