X=7-y
z=-1-y
(-1-y)+(7-y)=-2
6-2y=-2
-2y=-8
-y=-4
y=4
x=7-4=3
z=-1-4=-5
Сравните значения выражений,не вычисляя их: a)6,16-7,44 и 7,23+8,11; б)24,12*1/4 и 24,12:1/4; в)5,7-3,11 и 5,7-2,16;г)65,4*5/6 и
Анна1202 [30]
А 6.16-7.44<7.23+8.11
б 24.12×1/4>24.12:1/4
в5.7-3.11<5.7-2.16
г65,4×5/6>65,4÷5/6
(3√2/2)²=9*2/4=9/2 cos²α+sin²α=1
решение на фото
<span>Часть С</span><span>9) </span><span>1) [(b0,5 + 3)2 - (b0,5 - 3)2 ] / [b*[(b0,5 + 3) * (b0,5 - 3) ] = [b + 6b0,5 + 3
- b + 6b0,5 – 3] / b*(b – 9) = </span><span><span>= 12b0,5
/ b*(b – 9) = 12/</span>√b(b – 9) </span><span>2) [12/b0,5(b – 9)] * (b – 9)/b0,5
= 12 / b</span>
<span><span>10) </span>√<span>(9x2 – 6x + 1) = x2 + 1</span></span><span>(√<span>(9x2 – 6x + 1) )2
= (x2 + 1)2</span></span><span>9x2
– 6x + 1 = x4 + 2x2 + 1</span><span>x4
- 7x2 + 6x = 0</span><span>x(x3
– 7x + 6) = 0</span><span>x1
= 0</span><span>x3
– 7x + 6 = 0</span><span>x2
= 1</span><span> x3 – 7x +
6 <u>Ix
- 1
-(x3 – x2</u>) x2
+ x - 6
x2 – 7x
<u>-(x2 – x)</u>
- 6x + 6
<u>-(-6x + 6)
</u> 0</span><span>x3
– 7x + 6 = ( x – 1)( x2 + x – 6)</span><span> x2 + x – 6 = 0</span><span>x4 = 2</span><span>Ответ: x1 = 0; x2 = 1; x3 =
- 3; x4 = 2</span>
<span> </span>
X²-5x+6=0; - кввдратное уравнение
D=b²-4ac
D= 25-4*1*6=1;
икс1= -b + √D/2а=5+1/2=3
икс2= -b - √D/2a=5-1/2=2
Ответ:3,2