16) 6:2=3 см вторая сторона,верно
17)(2+3)*2=10 см периметр,а не 5 см -неверно
18) неверно
<span>9= 45/5,11=55/5,13=65/5,17=85/5</span>
4 5/12 - 1 1/2 : (2 1/6 + 8/15) * 1 4/5 = 3 5/12
1) 2 1/6 + 8/15 = 2 5/30 + 16/30 = 2 21/30 = 2 7/10
2) 1 1/2 : 2 7/10 = 3/2 : 27/10 = 3/2 * 10/27 = (1*5)/(1*9) = 5/9
3) 5/9 * 1 4/5 = 5/9 * 9/5 = 45/45 = 1
4) 4 5/12 - 1 = 3 5/12
2х-7+√(4х²-20х+25)=2х-7+√(2х-5)²=2х-7+(2х-5)=4х-12=4*2,5-12=-2
<span>-10y-64=6y
-10y-6y=64
-16y=64
y=-4
</span><span>16m-5=15m-10
</span>16m-15m=-10+5
m=-5
<span>40-12x=20-11x
40-20=12x-11x
20=x
x=20
</span><span>25-9y=5y+11
-5y-9y=-25+11
-14y=-14
y=1
</span><span>9m-8=6m+7
</span>9m-6m=8+7
3m=15
m=5
<span>8-5n=10-4n
-5n+4n=10-8
-n=2
n=-2</span>