\(21.7^2-11.7^2+90.7^2+49.125.16\)
\(=49.\left(21-11+90+125.16\right)\)
\(=49.2100\)
\(=102900\)
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`21.7^2 -11.7^2 +90.7^2 +49.125.16`
`=7^2(21-11+90)+49.25.5.4.4`
`=7^2 .100+100.49.20`
`=49.100+100.49.20`
`=49.100(1+20)`
`=49.100.21`
`=102900`
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21.72−11.72+90.72+49.125.16= 21.49-11.49+90.49+49.125.16
=49.(21−11+90+125.16)
=102900
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