5)
<u>87^3-43^3
</u>
87*43+ 44
87³-43³=(87-43)(87²+87*43+43²)=44(87²+87*43+43²)
87*43+87²+87*43+43²
87²+2(87*43)+43²
(43+87)²
130²
16900
(4х-10)/4=arccos(√2/2)=π/4+2πn, n∈Z
(4.4а+5.2b)²=(4.4a)²+(5.2b)²=19.36a²+27.04b²
(5.2x+3.6y)²=(5.2x)²+(3.6y)²=27.04x²+12.96y²