Ответ:
Объяснение:
х²+2ху+у²-3х-3у+5=(х+у)² - 3(х+у) +5
если х+у=2 то (2)²- 3*2+5=4-6+5= 3
Tg(a + π/4) = (tga + 1) / (1 - tga) = 0.2
0.2*(1 - tga) = tga + 1
0.2 - 0.2tga = tga + 1
-0.8 = 1.2tga
tga = -0.8/1.2
ctga = 1/tga = -1.2/0.8 = 1.5
!!!!!!!!!!!!!!!!!!!!!!!!!!
1) 1/4x = 8
x = 8 : 1/4
x = 32
2) 5x-12.5 = 0
5x = 12.5
x = 12.5 / 5
x = 2.5
3) 3x-0.6=x+4.4
2x = 5
x = 5/2
x = 2.5
4) 4x-(7x-2)=17
4x-7x+2=17
-3x=15
x=15/(-3)
x=-5
5(0,6- 1,5p)+8 - 3,5p = <span>3- 7,5p+8 - 3,5p = 11-11р</span>