3a+8=5-6a;
3a+6a=5-8;
9a=-3;
a=-1/3;
Ответ: -1/3
1. a) 9x^2–1=(3x–1)(3x+1)
б) 1/49–16с^2=(1/7–4с)(1/7+4с)
в) –100а^2+b^2=(b–10a)(b+10a)
г) x^2y^2–4=(xy–2)(xy+2)
д) n^4–1/144=(n^2–1/12)(n^2+1/12)
е) x^6–y^8=(x^3–y^4)(x^3+y^4)
2. (21^5–15^2)/18=(21–15)(21+15)/18=
=(6*36)/18=12
3. a) x^2–64=0
x^2=64
x1=8; x2=-8
б) х^2+9=0
х^2=-9
Решения нет
x^3-3x^2+3x-1=(1-x)(5-3x)
x=6-y
6-y+y+y(6-y)²+y²(6-y)=24
6+y³-12y²+36y+6y²-y³=24
-6y²+36y-18=0
y²-6y+3=0
D= 36-12= 24
y1= (6+√24)/2= 3+√6
y2= (6-√24)/2= 3-√6
x1= 6-3-√6= 3-√6
x2= 6-3+√6= 3+√6
пары чисел: (3-√6;3+√6) и (3+√6;3-√6)