Đáp án:
Giải thích các bước giải:
a. x-y=2 và 2x-3y =1
x - y = 2
=> x = 2 + y
2x - 3y = 1
=> 2( 2 + y ) - 3y = 1
=> 4 + 2y - 3y = 1
=> 4 - y = 1
=> y = 3
b, 7x - 2y =1 và 3x+y=6
3x + y = 6
=) y =3x - 6
7x - 2y = 1
=) 7x - 2( 3x - 6) = 1
=) 7x - 6x + 12 = 1
=) x = -11
c, 2x-y=5 va 2x+2y=20
2x - y = 5
=) y = 2x - 5
2x + 2y = 20
=) 2x + 2( 2x - 5 ) = 20
2x + 4x - 10 = 20
6x = 30
x = 5
Làm hộ mình 88,89 nhanh nha mình đang cần gấp
x mu 197=xmu 2 mong ddc giai nhanh
Tìm nghiệm của đa thức: N(x) = 2x^4 + x^2 + 1
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1. Public ..... in my town is good and cheap. A. transport B. tour C. journey D. travel 2. ..... Is not very far from here to the city centre. A. That B. This C. It D. There 3. When there is a traffic jam, it ..... me a very long time to go home. A. costs B. takes C. lasts D. spends 4. Mai's dad usually drives her to school ..... her school is very far from her house. A. but B. though C. because D. or 5. Yesterday Hoa and Lan ..... round West Lake. It took them an hour. A. cycle B. cycles C. cycling D. cycled
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