Question

sử dụng hằng đẳng thức để tính nhanh

\(205^2-95^2\)

\(36^2-14^2\)

\(97^2-3^{2^{ }}\)

\(89^2-18.89+9^2\)

\(41^2+82.59+59^2\)

\(1,24^2-2,84.0,24+0,24^2\)

Answer 1

\(205^2-95^2=\)

\(=\left(205-95\right)\left(205+95\right)\)

\(=200.300\)

\(=60000\)

\(36^2-14^2=\)

\(=\left(36-14\right)\left(36+14\right)\)

\(=22.50\)

\(=1100\)

Answer 2

\(205^2-95^2=\left(205-95\right)\left(205+95\right)=110.300=33000\)

\(36^2-14^2=\left(36-14\right)\left(36+14\right)=22.50=1100\)

\(97^2-3^2=\left(97-3\right)\left(97+3\right)=94.100=9400\)

Answer 3

\(205^2-95^2=\left(205+95\right)\left(205-95\right)=300.110=3.100.11.10=33000\)

\(36^2-14^2=\left(36+14\right)\left(36-14\right)=50.22=1100\)

\(97^2-3^2=\left(97+3\right)\left(97-3\right)=100.94=9400\)

\(89^2-18.89+9^2=\left(89-9\right)^2=80^2=6400\)

\(41^2+82.59+59^2=\left(41+59\right)^2=100^2=10000\)

\(1,24^2-2,84.0,24+0,24^2=\left(1,24-0,24\right)^2=1^2=1\)

Answer 4

\(205^2-95^{2^{ }}=\left(205-95\right)\left(205+95\right)\)

\(=200.300=60000\)

\(36^2-14^2=\left(36-14\right)\left(36+14\right)\)

\(=22.50\)\(=1100\)

\(97^2-3^2=\left(97-3\right)\left(97+3\right)=94.100\)

\(=9400\)

\(89^2-18.89+9^2=\left(89-9\right)_{ }^2\)

\(=80^2=6400\)

\(41^2+82.59+59^2=\left(41+59\right)^2\)

\(=100^2=10000\)

\(1,24^2-2,84.0,24+0,24^2=\left(1,24-0,24\right)^2\)

\(=1^2=1\)

Answer 5

TL:

a) \(205^2-95^2=\left(205+95\right)\left(205-95\right)=300.110=33000\) 

b) \(36^2-14^2=\left(36+14\right)\left(36-14\right)=50.22=1100\) 

d)\(89^2-18.59+9^2=\left(89-9\right)^2=80^2=6400\) 

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