A(b+4)+b(a+4)=(a+4)(b+4)
ab+4a+ab+4b=ab+4b+4a+16
2ab+4a+4b=ab+4b+4a+16
2ab-ab+4a-4a+4b-4b=16
ab=16
Ответ: D) 16.
2.
(a-3)(b-3)-(a+2)(b+2)=ab-3b-3a+9-(ab+2b+2a+4)=
=ab-3b-3a+9-ab-2b-2a-4=
=-5b-5a+5=(-5b-5a)+5=-5(a+b)+5= -5*(-3)+5=15+5=20
Ответ: В) 20.
3.
(3x²+5x-3)(4x+a)=12x³+20x²-12x+3x²a+5xa-3a
20x²+3x²a=x²(20+3a)
20+3a=0
3a= -20
a= -20/3
a= -6 ²/₃
Ответ: А) -6 ²/₃
4.
a²-4ab-3b²=(a²-4ab+4b²)-b²=(a-2b)²-b²=(a-2b-b)(a-2b+b)=(a-3b)(a-b)=
=(2.5-3*(-0.5))*(2.5-(-0.5))=(2.5+1.5)(2.5+0.5)=4*3=12
Ответ: А) 12
6.
A-(B-2A-(2B-2A))=A-(B-2A-2B+2A)=A-(-B)=A+B=
=5a²-2ab²-3b²+3a²+2ab+b²=8a²-2b²
Ответ: В) 8a²-2b²
7.
6ay-3ax+12by-6bx=(6ay-3ax)+(12by-6bx)=3a(2y-x)+6b(2y-x)=
=(2y-x)(3a+6b)=-(x-2y)*3*(a+2b)=-(-4.5)*3*4=4.5*12=54
Ответ: D) 54
10.
-3(4,4-5.2a)+2.1(3a-1.5)-2.8a=
=-13.2+15.6a+6.3a-3.15-2.8a=
=19.1a-16.35
Ответ: С) 19,1а -16,35
11.
3x- ⁵/₈ (3x-1)= ²/₃ (x+3)
24(3x- ⁵/₈ (3x-1))= 24 * ²/₃ (x+3)
72x-15(3x-1)=16(x+3)
72x-45x+15=16x+48
27x-16x=48-15
11x=33
x=3
Ответ: А) 3.
4sin(180-+45)-6cos(180-60)+tg(360-60)=3ctg(180+60)=
-4*sqrt(2)/2+6*1/2- sqrt(3)+3/ sqrt(3) =-2 sqrt(2)+3- sqrt(3)+ sqrt(3)=3- sqrt(2)
Решение
<span>a) 30</span>°<span> = (</span>π*30)/180 = π/6
<span> б) 45</span>°<span> = (</span>π*45)/180 = π/4<span>
в)120</span>°<span> = (</span>π*120)/180 = 2π/3<span>
г) 90</span>°<span> = (</span>π*90)/180 = π/2<span>
д) 240</span>°<span> = (</span>π*240)/180 = 4π/3
2)12p³-(1/3)p²-1-3p×(3/3)×p²=
=12p³-(1/3)p²-1-3p×1p²=
=12p³-(1/3)p²-1-3p³=9p³-(1/3)p²-1=
=(1/3)(27p³-p²-3)
4)5x+(1/5)x-20+x+(17/20)-5x=
=(1/5)x-20+x+(17/20)=(6/5)x-(383/20)=
=1/20(24x-383)
6)64-(2ab/(a-8)²)+2ab-(a²/(8-a)²)=
=64-(2ab/(a-8)²)+2ab-(a²/(-(a-8))²)=
64-(2ab/(a-8)²)+2ab-(a²/(a-8)²)=
64(a²-16a+64)-2ab+2a³b-32a²b+128ab
-a²/(a-8)²=
63a²-1024a+4096+126ab+2a³b-32a²b/(a-8)²
Большеникакнесократить!
8)x²+(6/x²)-9-(3(2x-1)/9)-x²=
=(6/x²)-9-((2x-1)/3)=
=(18-27x²-x²(2x-1))/3x²)=
=((18-27x²-2x³+x²)/3x²)=
=((-2x³-26x²+18)/3x²)
