Решите пошу, срасибо

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Решите пошу, срасибо


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Алгебра (143 баллов) | 39 просмотров
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Правильный ответ
1. a)\left \{ {{3x-2\ \textless \ 2+5x} \atop {8x\ \textgreater \ 15-2x}} \right.
\left \{ {{3x-5x\ \textless \ 2+2} \atop {8x+2x\ \textgreater \ 15}} \right.
\left \{ {{-2x\ \textless \ 4} \atop {10x\ \textgreater \ 15}} \right.
\left \{ {{x\ \textgreater \ -2} \atop {x\ \textgreater \ 1,5}} \right.
x∈(1,5;+∞)
б)
\left \{ {{5x\ \textless \ 4+10x} \atop {6x+1\ \textgreater \ 1+4x}} \right.
\left \{ {{5x-10x\ \textless \ 4} \atop {6x-4x\ \textgreater \ 1-1}} \right.
\left \{ {{-5x\ \textless \ 4} \atop {2x\ \textgreater \ 0} \right.
\left \{ {{x\ \textgreater \ -0,8} \atop {x\ \textgreater \ 0}} \right.
x∈(0;+∞)
2.а)\frac{y-xy}{3} * \frac{6}{1- x^{2} }- \frac{y}{1+x} = \frac{y(1-x)*6}{(1-x)(1+x)*3}- \frac{y}{1+x} = \frac{2y}{1+x} - \frac{y}{1+x} = \frac{2y-y}{1+x}= \frac{y}{1+x}
б)
\frac{3a}{1+c}- \frac{4}{1-c^2} * \frac{a-ac}{2}= \frac{3a}{1+c}- \frac{4*a(1-c)}{2(1-c)(1+c)} = \frac{3a}{1+c} - \frac{2a}{1+c} = \frac{3a-2a}{1+c}= \frac{a}{1+c}
3.а)
\frac{6^{-4}*6^{-9}}{6^{-12}} = \frac{6^{-4+(-9)}}{6^{-12}}= \frac{6^{-13}}{6^{-12}} = 6^{-13-(-12)}=6^{-13+12}=6^{-1}= \frac{1}{6}
б)
\frac{7^{-7}*7^{-8}}{7^{-13}} = \frac{7^{-7+(-8)}}{7^{-13}} = \frac{7^{-15}}{7^{-13}} =7^{-15-(-13)}=7^{-15+13}=7^{-2}= \frac{1}{7^2} = \frac{1}{49}
4.а)
\left \{ {{x+y=-2} \atop {y^2-3x=6}} \right.
Домножим на 3 первое уравнение системы и сложим со вторым:
\left \{ {{3x+3y=-6} \atop {y^2-3x=6}} \right.
\left \{ {{x+y=-2} \atop {y^2+3y=0}} \right.
\left \{ {{x+y=-2} \atop {y(y+3)=0}} \right.
\left \{ {{x=-2-y} \atop {y_1=0;y_2=-3}} \right.
\left \{ {{x_1=-2-0; x_2=-2-(-3)} \atop {y_1=0;y_2=-3}} \right.
\left \{ {{x_1=-2; x_2=1} \atop {y_1=0;y_2=-3}} \right.
б)
\left \{ {{x+y=5} \atop {x^2-3y=-15}} \right.
Домножим на 3 первое уравнение системы и сложим со вторым:
\left \{ {{3x+3y=15} \atop { x^{2} -3y=-15}} \right.
\left \{ {{x+y=3} \atop { x^{2} +3x=0}} \right.
\left \{ {{y=5-x} \atop {x(x+3)=0}} \right.
\left \{ {{y=5-x} \atop {x_1=0; x_2=-3}} \right.
\left \{ {{y_1=5-0; y_2=5-(-3)} \atop {x_1=0; x_2=-3}} \right.
\left \{ {{y_1=5; y_2=8} \atop {x_1=0; x_2=-3}} \right.
5.а)
-4\ \textless \ 2x-1\ \textless \ 2
-4+1\ \textless \ 2x\ \textless \ 2+1
-3\ \textless \ 2x\ \textless \ 3
\frac{-3}{2} \ \textless \ x\ \textless \ \frac{3}{2}
-1,5\ \textless \ x\ \textless \ 1,5
x∈(-1,5; 1,5)
б)-6\ \textless \ 5x-1\ \textless \ 5
<img src="https://tex.z-dn.net/?f=-6%2B1%5C+%5Ctextless+%5C+5x%5C+%5C
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