(a +b)² = a² +2ab +b²
x² +10x +25 =0
x² + 2*5x + 5² = 0
(x+5)² = 0
√(x+5)² = √0
x+5 = 0
x = -5
1)
2y^2-(b-2c)y=bc = 2y^2-(b-2c)y-bc = 2y^2-by+2cy-bc = (2y-b)(y+c)
2)
abx^2-(a^2-b^2)x-ab=0 = abx^2-a^2x+b^2x-ab = (bx-a)(ax+b)
15/(x-1.5)-18/(x+1.5)=0.5
(15/(x-1.5)-18/(x+1.5))*(x-1.5)=0.5*(x-1.5)
(-6x+99)/(2x+3)=0.5x-0.75
(-6x+99)/(2x+3)*(x+1.5)=(0.5x-0.75)*(x+1.5)
-3x+49.5=0.5x²-1.125
-0.5x²-3x+50,625=0
x1=-13.5 x2=7.5
7.5+1.5=9
7.5-1.5=6
18/9=2
15/6=2.5
2.5-2=0.5
15/(x-1.5)-18/(x+1.5)=0.5
-0.5x²-3x+50,625=0
x1=-13.5
x2=7.5
Ответ: 7,5 км в час
225a^4b^2=(15a^2b)^2. ^- это степень.