Ответ смотри в приложении
1) 5x²-5y²=5(x²-y²)=5(x-y)(x+y)=5(49-51)(49+51)=5*(-2)*100=-10*100=-1000.
2) 3a²-6ab+3b²=3(a²-2ab+b²)=3(a-b)²=3*(102-101)²=3*1²=3*1=3.
2) (4b - 1)(4b + 1) - (4b - 1)² = 16b² - 1 - (16b² - 8b + 1) = 16b² - 1 - 16b² + 8b - 1 = 8b - 2
При b = - 4: 8 * (- 4) - 2 = - 32 - 2 = - 34
3)
3x + 2 (4x - 7) = 8
3x + 8x - 14 = 8
11x = 8 + 14
11x = 22
x = 2
Ответ: 1
4. А1, Б3, В2
1)
(2t+4.3)(7t+8)=14t²+16t+30.1t+34.4=14t²+46.1t+34.4
2)
(-7-p)(m-4)=-7m+28-pm-4p
3)
(t+1)(t-7)-t²=t²-7t+t-7-t²=-6t-7
-6(-5)-7=30-7=23
4)
90z²+4=(5z+1)(18z+5)
90z²+4=90z²+25z+18z+5
4=25z+18z+5
4=43z+5
-43z=5-4
-43z=1
z=-(1/43)
5)
(0.1z+4s)(0.01z²-0.4zs+16s²)
0.001z³-0.16z²s+1.6zs²+0.04z²s-1.6zs²+64s³
0.001z³-0.12z²s+64s³
6)
(2u²+3)(3u-9)*u²=(6u³-18u²+9u-27)u²
6u^5-18u⁴+9u³-27u²
7)
(q-2)(7q+1)(4q-7)=(7q²+q-14q-2)(4q-7)
(7q²-13q-2)(4q-7)=28q³-49q²-52q²+91q-8q+14
28q³-101q²+83q+14