<span> 7c(4c+2)^2=28c^2+14c-7+c^2 </span>
7с( 16с^2+16c+3) = 28c^2+14c-7+c^2
112c^3+112c^2+28c= 28c^2+14c-7+c^2
112c^3+112c^2+28c - 28c^2-14c-7+c^2 = 112c^3+85c^2+14c-7
12ab²=144a²b²
b+3ab²=b²+9a²b²
Ну вот так,надеюсь,что правильно
1 3/4 = 7/4
2 4/5 = 14/5
7/4 + 14/5 = 35/20 + 56/20 = 91/20
91/20 * 30/1 =(91*3)/2 =273/2 = 136 1/2
2*x+3/4+x/3=x+1/2
x*(2+1/3-1)=1/2-3/4
x*4/3= - 1/4
x= - 3/16
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