42.
(b+6)(b-6)-b(b+5) при b= -3/5
(b+6)(b-6)-b(b+5)=b²-36-b²-5b=-36-5b
-36-5b=-36-5(-3/5)=-36+3=39
43.
(3-x)²+(4-x)(4+x) при x=5/6
(3-x)²+(4-x)(4+x)=9-6x+x²+16-x²=25-6x
25-6x=25-6•5/6=25-5=20
44.
(2+a)²+(5-a)(5+a) при а=-3/4
(2+a)²+(5-a)(5+a)=4+4а+а²+25-а²=29+4а
29+4а=29+4(-3/4)=29-3=26
45.
(4-с)²+(2-с)(2+с) при с=-3/8
(4-с)²+(2-с)(2+с)=16-8с+с²+4-с²=20-8с
20-8с=20-8(-3/8)=20+3=23
46.
(m+1)²+(6-m)(6+m) при m=1/2
(m+1)²+(6-m)(6+m)=m²+2m+1+36-m²=36+2m
36+2m=36+2•1/2=36+1=37
47.
-m(m+2)+(m+3)(m-3) при m=1/2
-m(m+2)+(m+3)(m-3)=-m²-2m+m²-9=-2m-9
-2m-9=-2•1/2-9=-10
48.
-p(4+p)+(p-2)(p+2) при p=3/4
-p(4+p)+(p-2)(p+2)= -4p-p²+p²-4=-4p-4
-4p-4=-4•3/4-4=-3-4=-7
49.
(n+6)²+(2-n)(2+n) при n=-5/12
(n+6)²+(2-n)(2+n)=n²+12n+36+4-n²=40+12n
40+12n=40+12(-5/12)=40-5=35
5^(x-2) = 5^0 2^(x² -3x +8) = 2^6
x-2 = 0 x² -3x +8 = 6
x = 2 x² -3x +2 = 0
2) 3·4^x =48 x = 1 и х = 2
4^x = 16 6)7^(2x-8)·7^(x+7) = 0
4^x = 4² нет решений
x=2 7)(0,2)^x ≤ 25·5√5
3)3^x=27·3√9 5^-x ≤ 5²·5·5^1/2
3^x = 3³·3·3 5^-x ≤5^3,5
3^x = 3^5 -x ≤ 3,5
x = 5 x ≥ -3,5
4)3^x + 3^(x +1) = 4 8)(1/2)^-x + 2^(3 +x) ≤9
3^x(1 +3) = 4 2^x +2^(3 +x) ≤ 9
3^x·4 = 4 2^x(1 +2^3) ≤ 9 | :9
3^x = 1 2^x ≤ 1
x = 0 2^x ≤2^0
x≤ 0
42.
(b+6)(b-6)-b(b+5) при b= -3/5
(b+6)(b-6)-b(b+5)=b²-36-b²-5b=-36-5b
-36-5b=-36-5(-3/5)=-36+3=39
43.
(3-x)²+(4-x)(4+x) при x=5/6
(3-x)²+(4-x)(4+x)=9-6x+x²+16-x²=25-6x
25-6x=25-6•5/6=25-5=20
44.
(2+a)²+(5-a)(5+a) при а=-3/4
(2+a)²+(5-a)(5+a)=4+4а+а²+25-а²=29+4а
29+4а=29+4(-3/4)=29-3=26
45.
(4-с)²+(2-с)(2+с) при с=-3/8
(4-с)²+(2-с)(2+с)=16-8с+с²+4-с²=20-8с
20-8с=20-8(-3/8)=20+3=23
46.
(m+1)²+(6-m)(6+m) при m=1/2
(m+1)²+(6-m)(6+m)=m²+2m+1+36-m²=36+2m
36+2m=36+2•1/2=36+1=37
47.
-m(m+2)+(m+3)(m-3) при m=1/2
-m(m+2)+(m+3)(m-3)=-m²-2m+m²-9=-2m-9
-2m-9=-2•1/2-9=-10
48.
-p(4+p)+(p-2)(p+2) при p=3/4
-p(4+p)+(p-2)(p+2)= -4p-p²+p²-4=-4p-4
-4p-4=-4•3/4-4=-3-4=-7
49.
(n+6)²+(2-n)(2+n) при n=-5/12
(n+6)²+(2-n)(2+n)=n²+12n+36+4-n²=40+12n
40+12n=40+12(-5/12)=40-5=35