Question

không làm tắt. nha mn

Answer 1

Bài 1:

a) \(x^2-7x=x\left(x-7\right)\)

b) \(5x-10y=5\left(x-2y\right)\)

c) \(5x^2-15xy=5x\left(x-3y\right)\)

d) \(3\left(x-y\right)-y+x=3\left(x-y\right)+x-y=4\left(x-y\right)\)

e) \(5\left(x-y\right)-x^2+xy=5\left(x-y\right)-x\left(x-y\right)=\left(x-y\right)\left(5-x\right)\)

Answer 2

Bài 2 : 

a, \(75.20,9+5^2.20,9=20,9\left(75+25\right)=20,9.100=2090\)

b, \(85.15+150.1,4=85.15+15.14=15.99=1485\)

c, \(93.32+14.16=186.16+14.16=16.200=3200\)

d, \(98,6.199-990.9,86=98,6.199-99.98,6=98,6.100=9860\)

Answer 3

Bài 2: 

a) Ta có: \(75\cdot20,9+5^2\cdot20,9\)

\(=20,9\left(75+25\right)\)

\(=20,9\cdot100=2090\)

b) Ta có: \(85\cdot15+150\cdot1,4\)

\(=85\cdot15+14\cdot15\)

\(=15\left(85+14\right)\)

\(=15\cdot99=1500-15=1485\)

c) Ta có: \(93\cdot32+14\cdot16\)

\(=93\cdot2\cdot16+14\cdot16\)

\(=16\left(186+14\right)\)

\(=16\cdot200=3200\)