Question

Dùng hằng đẳng thức tính nhanh a,15^2 -10.15+5^2 b,99^2-1 ai giúp với

Answer 1

\(a,15^2-10.15+5^2=15^2-2.5.15+5^2=\left(15-5\right)^2=10^2=100\\ b,=99^2-1=\left(99-1\right)\left(99+1\right)=98.100=9800\)

Answer 2

.\(15^2-10.15+5^2=15^2-2.15.5+5^2=\left(15-5\right)^2=10^2=100\\ 99^2-1=\left(99-1\right)\left(99+1\right)=98.100=9800\)

Answer 3

\(a,15^2-10.15+5^2=15^2-2.15.5+5^2\\ =\left(15-5\right)^2=10^2=100\)

\(b,99^2-1=99^2-1^2\\ =\left(99-1\right)\left(99+1\right)\\ =98.100=9800\)