( 3m - 4n )( 3m + 5n ) - ( 4,5m - n )( 2m + 4n ) = 9m² + 15mn - 12mn - 20n² - ( 9m² + 18mn - 2mn - 4n² ) = 9m² - 20n² + 3mn - ( 9m² - 4n² + 16mn ) = 9m² - 20n² + 3mn - 9m² + 4n² - 16mn = 24n² - 13mn
Y(2-x)=5
2y-xy=5
-xy=5-2y
x=-(5-2y)/y
<span>A+b+a2-b2 = ( a + b ) + ( a + b )( a - b ) = ( a + b )( 1 + a - b )</span>
3х-64=125
3х=64+125
3х=189
х=189:3
х=63