X - 1 = 4(2x + 5)
x - 1 = 8x + 20
8x - x = - 1 - 20
7x = - 21
x = - 3
3x^2+4x-16=(x-4)^2
3x^2+4x-16=x^2-8x+16
2x^2+12x-32=0
x^2+6x-16=0
D= 36+64=100
x1=-6-10/2=-8
x2=-6+10/2=2
Б 10....................................................................................................................................................
6,2 < a < 6,3
38,44 < a² < 39,69
1,0 < b < 1,2
1 < b² < 1,44
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37,44 < a² - b² < 38,25