Question

Решите уравнение
1. (8x+2.4):3 = 1.8
2. x:16 = 3целых 3/4 : 6целых 2/3
3. -0.2x * (-0.7) = 0.84
4. 1/3x + 2целых 2/5 =3 целых 2/3
5. 2 * l 4- x l=9
6. -2 целых 1/5 + x = -5целых 1/2
7. (x - 12)(3-x)=0
8. 8.8-(x + 4.9) = - 18.6
9.7/9x +11/12=13/18
10. -0.8(x-1.5)=6.4
11. (3/8x - 9/16)(0.8 +x) = 0
12. -8.9-(3.7-x)=- 13.6
13 3*(0.4-x)=9
14 2*l x-3 l=5

Answer 1

1) 8x+2.4=1.8*3; 8x=1.8*3-2.4; x=(1.8*3-2.4)/8=3/8=0.375
2) x/16=15*3/4*20; x=15*3*16/4*20=3*3*4/4=9
3) -0.2x* (-0.7)=0.14x; 0.14x=0.84; x=6
4)1/3x=3 2/3- 2 2/5; 1/3x=1 4/15; x=1 4/15 : 1/3; x=3 4/5=3.8
5) 2*(4-x)=9; 8-2x=9; 2x=-1; x=-1/2 
2*(x-4)=9 ; 2x-8=9; 2x=17; x=17/2=8 1/2=8.5
6) x=-5 1/2 +2 1/5=-3 5-2/10=-3.3
7) (x-12)(3-x)=0; 3x-36-x2+12x=0; 15x-36-x2=0; x2-15x+36=0; D=225-144=81;
x1,2=15+-9/2=12, 3
8) x=8.8-4.9+18.6=22.5
9) 7/9x=13/18-11/12; 7/9x=7/36; x=7*9/36*7=1/4=0.25
10) -0.8x+1.2=6.4; 0.8x=1.2-6.4; 0.8x=-5.2; x=-6.5
11) 0.3x+3/8x2-0.45-9/16x=0; 3/8x2-21/80x-45/100=0 |*80 ; 30x2-21x-180/5=0 |*5;
150x2-105x-180=0; D=11025+108000=119025; x1,2=105+-345/300=1.5,-0.8
12) x=-13.6+8.9+3,7=-1
13) 3x=1.2-9; x=-7.8/3=-2.6
14) 2*(x-3)=5; 2x=11; x=11/2=5.5
2*(3-x)=5; 2x=6-5; x=1/2=0.5
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