Question

Tìm các cặp số x, y thỏa mãn:

a) ( 2x - 1 )( 2y + 1 ) = - 35.

b) ( x - 3 ) - 5x + 15 = 7.

c) y( x - 7 ) - 2x + 14 = 5.

Answer 1

b: =>x-3-5x+15=7

=>-4x+12=7

=>-4x=-5

hay x=5/4

c: =>y(x-7)-2(x-7)=5

=>(x-7)(y-2)=5

\(\Leftrightarrow\left(x-7;y-2\right)\in\left\{\left(1;5\right);\left(5;1\right);\left(-1;-5\right);\left(-5;-1\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(8;7\right);\left(12;3\right);\left(8;-3\right);\left(2;1\right)\right\}\)