Решение
<span>√(45 + 4x) = x
</span><span>{√(45 + 4x) = x,
</span>{x > 0.
(√(45 + 4x))² = x²
45 + 4x = x²
x² - 4x - 45 = 0
D = 16 + 4*1*45 = 16 + 180 = 196
x = (4 - 14)/2
x = - 5 не удовлетворяет условию: x > 0
x = (4 + 14)/2
x = 9
Ответ: x = 9<span> </span>
26 - 3
28 - 1
29 - 3 (или 1)
30 - 1
1.4×1.5=2.1
1.8+2.1=3.9
1.8×1.2=2.16
1.5×1.4=2.1
2.16-2.1=0.06
3.9÷0.06=65
<span>(x+1)(x+2)(x+3)(x+4)=3</span>
(7cosa - 4(2cos²a-1))/(4cos²a-(2cos²a-1))=(-cos²a+4)/(2cos²a+1)