Mathematics
mirnabeauge
32

( directions are on the picture . And also just comment and answer if you know any and can explain how to do them please ! I really need help) Answer any that you know and can explain for a brainliest and also a thanks ! Don't answer if you don't know it .

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(1) Answers
Genna57

just need to do FOIL which is first outter inner last first one (x+4)(x-4) first: x*x=x² inner: 4*x=4x outer:x*-4=-4x last:4*-4=-16 add x²+4x-4x-16=x²-16=x²-4² basically a²-b²=(a+b)(a-b) so (5x+1)(5x-1)=(5x)²-1²=25x²-1 (2a+3b)(2a-3b)=(2a)²-(3b)²=4a²-9b² you can check the foils with very little brainwork basically notice that (a+b)(a-b) ends up with a²+ab-ab+b², the ab's in middle cancle out all the time 1. 4=2² a²-2²=(a+2)(a-2) 2. 64=8² n²-8²=(n+8)(n-8) 3. 81=9² 9²-x²=(9+x)(9-x) 4. 100=10² c²-10²=(c+10)(c-10) 5. 25=-25*-1=-5²*i²=-(5i)²    (i=√-1) k²-(5i)²=(k+5i)(k-5i) 6. 49y²=(7y)² 1²-(7y)²=(1+7y)(1-7y) 7. 9b²=(3b)² (3b)²-10²=(3b+10)(3b-10) 8. 25x²=(5x)² (5x)²-7²=(5x+7)(5x-7) 9. 16a²=(4a)² 121=11² (4a)²-11²=(4a+11)(4a-11) 10. 81y²=(9y)² x²-(9y)²=(x+9y)(x-9y) 11. 4h²=(2h)² 25g²=(5g)² (2h)²-(5g)²=(2h+5g)(2h-5g) 12. 64u²=(8u)² (8u)²-v²=(8u+v)(8u-v) 13. x²y²=xxyy=(xy)(xy)=(xy)² (xy)²-1²=(xy+1)(xy-1) 14. 81n⁴=(9n²)² (9n²)²-5²=(9n²+5)(9n²-5) notice we can further factor the last factor (9n²-5) with (3n)²-(√5)² to obtain (3n+√5)(3n-√5) in all, the factored form complete is (9n²+5)(3n+√5)(3n-√5) not including imaginary numbers

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