2) a) (x+1)²=x²+2x+1
b) (x–2)²=x²–2x+4
c) (x+3)(x–3)=x²–9
d) (√2+1)²=2+√2√2+1
e) (√3+1)(√3–1)=3–1=2
3) a) 4x²+6x=2x(x+3)
b) x²-6x+9=(x–3)²
c) x²–10x+25=(x–5)²
d) 4x²–1=(2x–1)(2x+1)
4) a) x+3=8
x=8–5
x=3
b) 10–x=6
–x=6–10
–x=–4 |*(-1)
x=4
c) 12:x=4
x=4×12
x=48
d) x+1=2x+5
x–2x=4–1
–x=3 |(-1)
x=–3
e) x+1<5
x<5–1
x<4
f) 5–x<2
–x<2–5
–x<–3|(–1)
x<3
5) Cati elevi sunt in clasa?
1+2+5+6+4+2+1+1=22 de elevi
Cati elevi au luat cel putin nota 7 ?
18 elevi
