Question

Tính nhanh:

a) 75²-50.75+25²

b) 103.97

Answer 1

\(a.75^2-50.75+25^2\\ =75^2-2.25.75+25^2\\ =\left(75-25\right)^2=50^2=2500\)

\(b.103.97\\ =\left(100+3\right)\left(100-3\right)\\ =100^2-3^2\\ =9991\)

Answer 2

\(a,75^2-50.75+25^2\\ =75^2-2.75.25+25^2\\ =\left(75+25\right)^2=100^2=10000\\ b,103.97\\ =\left(100+3\right).\left(100-3\right)\\ =100^2-3^2=10000-9=9991\)

Answer 3

a) \(75^2-2\cdot25\cdot75+25^2\)

= \(\left(75+25\right)^2\)

= \(100^2=10000\)
b) \(103\cdot97\)

= \(\left(100+3\right)\left(100-3\right)\)

= \(100^2-3^2\)

= \(10000-9=9991\)