Решение во вложении----------------------------------------
X-y=0⇒x=y.
x+y=10⇒x+x=2*x=10⇒x=5⇒y=5.
Ответ: х=5; y=5.
C=20
b=20-5=15
a=20*3=60
S=2(ab+bc+ac)=2(60*15+15*20+60*20)=2(900+300+1200)=2*2400=4800 cм³
1) |-5,2 + 1,8| = 3.4
|-2/9 - 5/9| = 7/9
2)
a) -1/4 * (-6.94) * 0.4 = 0.694
b) 11/8 * (-3,47) * (-8) = 11*3.47 = 38.17
c) (-0.001) * (-5.4) * 50 * (-2) = (-0.1) * 5.4 = -0.54
3)
A)86.719*64.9 - 86.719*164.9 = 86.719*(64.9-164.9) = -8671.9
B) 2.3*(-1/2) + 3.7*(-1/2) = (-1/2)*(2.3+3.7) = -2.5
C) ( 3/4 - 1/9 + 2/3)*36 = 27 - 4 + 24 = 47