7 кг - х+840
3 кг - х
7х=3(х+840)
7х=3х+2520
7х-3х=2520
4х=2520
х=2520:4
х=630 (2-ой ящик)
630+840=1470 (1 ящик)
<u>0.13d-1.5</u> = 0.84 ÷7/15 - 1 3/5
<span>3 1/3
<u>
</u></span><u>0.13d-1.5</u> = 0.84 *15/7 - 1,6
<span>10/3
<u>
</u></span><u>0.13d-1.5</u> = 0,12 *15 - 1,6
<span>10/3
</span><u>
</u><u>0.13d-1.5</u> = 1,8 - 1,6
<span>10/3
</span><u>
</u><u>0.13d-1.5</u> = 0,2
<span>10/3
</span><u>
</u>0,13d-1.5=0.2*10/3
<span>0,13d-1 5/10=2/3
</span>0,13d-1 1<span>/2=2/3
</span>0,13d<span>=2/3+1 1/2
</span>0,13d<span>=4/6+1 3/6
</span>0,13d<span>=1 7/6
</span>0.13d=13/6
d=13/6:0,13=100/6=50/3=16 2/3
9-4x=3x-40
-4x-3x=-40-9
-7x=-49
x=-49:-7
X=7