1.
(х+4)²=х²+8х+16
(3b-c)²=9b²-6bc+c²
(2y+5)(2y-5)=4y²-25
(y²-x)(y²+x)=y^4 -x²
2.
9x²-4=(3x-2)(3x+2)
49-25y²=(7-5y)(7+5y)
4a²-20ab+25b²=(2a-5b)(2a-5b)=(2a-5b)²
8ab+b²+16a²=16a²+8ab+b²=(4a+b)²
3.
(a-2b)²+4b(a-b)=a²-4ab+4b²+4ab-4b²=a²
при а= - 3/2
(-3/2)²=3²/2²=9/4=2 1/4
4.
3(1+2xy)(1-2xy)=3(1-4x²y²)=3 - 12x²y²
(x² - y³)²=x^4 -2x²y³ + y^6
(a+b)² - (a-b)²=(a+b+a-b)(a+b-a+b)=2a*2b=4ab
5.
(4x-3)(4x+3)-(4x-1)²-3x=0
16x² -9 - 16x²+8x -1 -3x=0
5x - 10=0
5x=10
x=2
6.
234² - 233²=(234-233)(234+233)=1*467=467
139²+2*139*61+61²=(139+61)(139+61)=200*200=40000
159²-2*159*59+59²=(159-59)(159-59)=100*100=10000