(9*8+12):(4+2)=14
9*8=72
72+12=84
4+2=6
84:6=14
35:(5+2)*(12-4)+16=56
5+2=7
35:7=5
12-4=8
5*8=40
40+16=56
3 =3\1= 5 x 3\5 x 1 =15\5
1 = 1\1 =12 x 1\12x1=12\12
3 =15\5
1 =12\12
{2х-у=2 ⇒ y= 2x-2
{3х+у=8
3x + 2x-2 =8
5x=8+2
5x=10
x=2
y=2*2 -2 = 4
Ответ : (2;2)
{4х-3у=3 ⇒ y= (4x-3)/3
{4х-7у=-5
4x - 7/1 * (4x-3)/3 = -5
4x- ( 7(4x-3)/3) = -5 |×3
12 x - 7 (4x-3) = -15
12x - 28x + 21=-15
- 16x = - 36
x= (-36) / (-16) = 9/4
x= 2.25
y= ( 4*2.25-3) /3 = 6/3=2
Ответ: (2,25 ; 2)
{7x+3y=-1 ⇒ x= (-1-3y)/7
{3x - 7y= 17
3(-1-3y) /7 - 7y =17 |×7
3(-1-3y) -49y= 119
-3 -9y-49y=119
-58y=119+3
y= 122/(-58) = - 61/29
y= - 2 3/29
x= (-1 - 3/1 * (-61/29) ) /7 = (-29/29 + 183/29 )/7 =
= 154/29 * 1/7= 22/29
Ответ: ( 22/29 ; -2 3/29 )
920 там не получится , быть может там 902 , тогда так <span>1000-(990:10-1)</span>
960:(2+6)=120