1) 2b/5a-5a/2b = (4b²-25a²)/10ab
2) (4b²-25a²)/10ab*1/(2b+5a) = (2b+5a)(2b-5a)/10ab(2b+5a) = (2b-5a)/10ab
(2*1/9-5*1/5)/10*1/9*1/5 = (2/9-1)/2/9 = -7/9*9/2 = -7/2 = -3,5
Sin 45°=√2/2 cos 45°=√2/2
sin 45°+cos 45°=√2
7+2х^2=2х^2+8х+6
2х^2-2х^2-8х=6-7
-8х=-1
х=1:8
х=1/8
<span>1) (x-3)(x-11)<0
(х-3)(х-11)=0
х-3 =0 и х -11 = 0
х = 3 и х = 11
3 11
__о_____о_______>
+ - +
x</span>∈(-∞; 3)∪(11; +∞)