4b-3 .. you use distributive property and multiply 3*b-1 then you have 7b-3b-3 then you combine like terms and subtract 3b from 7b and get 4b-3
<span>4b^2 - 16 = (2b + 4)(2b - 4)
</span>difference of squares<span>
a^</span>2<span> – b^</span>2<span> = (a + b)(a – b) </span><span>
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