1) 5 4/15
2)3/8
3)3 8/9
4)26 1/12
Пошаговое объяснение:
1.
1) 17*5=85
2)85+3=88
3)12*3=36
4)36+1=37
5)88/5-37/3=264/15-185/15=79/15=5 4/15
2.
1)13*8=104
2)104+1=105
3)12*4=48
4)48+3=51
5)105/8-51/4=105/8-102/8=3/8
3.
1)41*9=369
2)369+2=371
3)37*3=111
4)111+1=112
5)371/9-112/3=371/9-336/9=35/9=3 8/9
4.
1)35*36=1260
2)1260+11=1271
3)9*9=81
4)81+2=83
5)1271/36-83/9=1271/36-332/36=939/36=26 3/36=26 1/12
7x+3\ \textgreater \ 5(x-4)+1
7x+3\ \textgreater \ 5x-20+1
7x-5x\ \textgreater \ -19-3
2x\ \textgreater \ -22
x\ \textgreater \ -11
2. 2 x^{2} +13x-7\ \textgreater \ 0
D=169+56=225
x_1= \frac{-13+15}{2*2} =0,5; x_2=\frac{-13-15}{2*2} =-7
x∈(-∞;-7)∪(0,5;+∞)
3. 2(1-x) \geq 5x(3x+2)
2-2x \geq 15 x^{2} +10x
2-2x-15 x^{2} -10x \geq 0
-15 x^{2} -12x+2 \geq 0
D=(-12)^2-4*(-15)*2=144+120=264
x_1= \frac{12+2 \sqrt{66} }{-30}= -\frac{6+ \sqrt{66} }{15} ; x_= \frac{12-2 \sqrt{66} }{-30}= -\frac{6- \sqrt{66} }{15}
x∈[-\frac{6+ \sqrt{66} }{15}; -\frac{6- \sqrt{66} }{15} ]
4. 3 x^{2} +5x-8 \geq 0
D=25-4*3*(-8)=25+96=121
x_1= \frac{-5+11}{2*3} =1; x_2= \frac{-5-11}{2*3} =- \frac{8}{3}
x∈(-∞;-8/3]∪[1;+∞)
Пошаговое объяснение:
1) 88/5 - 37/3 = (264-185)/15 = 79/15 = 5 4/15 (см)
2) 105/8 - 51/4 = (105-102)/8 = 3/8 (т)
3) 371/9 - 112/3 = (371-336)/9 = 35/9 = 3 8/9 (ч)
4) 1271/36 - 83/9 = (1271-332)/36 = 939/36 = 26 1/12 (кг)