Из основного свойства пропорции выражаем a:
a = (1.6*9 \ 0.8) = 9*2 = 18
ответ: a = 18
1)
(2x - 9)(x + 6) - x(x + 6) = 0
(x+6)(2x-9-x)=0
(x+6)(x-9)=0
x+6=0 x-9=0
x= - 6 x=9
2)
(8x+ 4)(x - 10) + (10 - x)(x - 8) = 0
(8x+ 4)(x - 10) - (x - 10)(x - 8) = 0
(x-10)(8x+4-x+8)=0
(x-10)(7x+12)=0
x-10=0 7x+12=0
x=10 7x= - 12 /:7
x= - 12/7
<span>1,7<</span><span>√3</span><span><1,8</span>
<span>1) 1.7*3<3√3<1.8*3</span>
<span>5.1<3√3<5.4</span>
<span>2) 1.7*2<2√3<1.8*2</span>
<span>3.4<2√3<3.6</span>
<span>5-3.4>5-2√3>5-3.6</span>
<span>1.6>5-2√3>1.4</span>
2x + x = 18
3 x = 18
x = 18 : 3
x = 6