А)(856-x)+125=378; б)900-(х-315)=508;
856-x=378-125; х-315=900-508;
856-х=253; х-315=392;
х=856-253; х=392+315;
х=603. х=707.
Ответ:х=603. Ответ:х=707.
2.17*4.3+0.84822:0.67=9,331+1,266=10,597
sin150<span>°</span>+sin75<span>°</span>=sin(180<span>°</span>-150<span>°</span>)+sin(30<span>°</span>+45<span>°</span>)= -sin30<span>°</span>+sin30<span>°*cos45<span>°+sin45<span>°*cos30<span>°= -1/2+ 1/2* <span>√2/2+ <span>√2/2*<span>√3/2= -1/2+<span>√2/4+<span>√6/4=(<span>√2+<span>√6-2)/4=<span>√2(1+<span>√3-<span>√2)/4</span></span></span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span><span><span>Ну как-то так</span></span></span></span></span></span></span></span></span></span></span></span></span></span>