1/b*x^2=2*x-b
x^2=2*b*x-b^2
x^2-2*b*x+b^2=0
D=4*b^2-4*b^2=0
x=2*b/2=b
x=b
2yz - 11yb - 26z + 143b = 2z(y - 13) - 11b(y - 13) = (2z - 11b)(y - 13)
Ответ:
7) 4/25 + 15/4 = 16+375/100 = 391/100 = 3 целых 91/100
8) 27/5*4 = 27/20 = 1 целая 7/20
9) 1 / 1/18-1/21 = 1/ 1/126 = 126
10) 18 * (1/9)^2 - 20 * 1/9= 18 * 1/81 - 20 * 1/9 = 2/9 - 20/9 = - 18/9 = -2
11) 0,9 / 1 + 1/8 = 9/10 делить на 9/8 = 4/5
12) 1/4 + 0,7 = 1/4 + 7/10 = 5+14/20 = 19/20
=a+3:<span>(a+3)</span><span>^2/<span>(a-3)<span>(a+3) = (сокращаем (a+3))</span></span></span>