-3,2 + (-3,9) = -3,2 - 3,9 = -(3,2 + 3,9) = -7,1
<span>624 1268-13965+190008= 6417311
</span><span>105* (6+203)-300/5=21885
</span><span>(6275-1829)*0+3500=3500 </span><span><span>
</span></span>
∠(aa1) = 180°.∠(ab) + ∠(a1b) = 180° (т.к. они смежные). ∠(a1b) = 180° - 60° = 120°.∠(ac) + ∠(a1c) = 180° (т.к. они смежные). ∠(a1c) = 180° - 30° = 150°, ∠(ab) = ∠(ac) + ∠(cb). ∠(cb) = ∠(ab) - ∠(ac) = 60° - 30° = 30°.