10-7x=x+26
10-26=x+7x
-16=8x
x=-2
2-3 (2х+5)= (3х-15)-6
2-6х-15=3х-15-6
2-6х=3х-6
-6х-3х=-6-2
-9х=-8
х=8/9
1) (х+у)^2+(х-у)<span>^2=х<span>^2+2ху+у^2+х^2-2ху+у^2=2х^2+2у^2=2(х^2+у^2)</span></span>