Question

Ajutor urgent! dau coroană!!!!!!!!!​

Answer 1

Răspuns:

1. a)-2x+3x-x=-3x+3x=0

b) (-2x²)²=4x⁴

c) -2x+4y+8z=2(-x+2y+4z)

d) E(x)=$\frac{2}{x-2}$ nu are sens daca este 0 ⇒

x-2≠0 ⇒ x≠2 ⇒ x∈R\{2}

2.a) $\frac{x^{2}-10x+25}{x^{2}-25}=\frac{(x-5)^{2} }{(x-5)(x+5)} =\frac{x-5}{x+5}$

b) (x-3)(x+3)=x²-9

c) $(-\frac{x^{2} }{y^{4}}):(-\frac{x^{4}}{y^{2}})=  \frac{x^{2} }{y^{4}}*\frac{y^{2}}{x^{4}}=\frac{1}{x^{2}y^{2} }$

d) E(x)=$\frac{3-x}{2}$

$E(\sqrt{2}+1)=\frac{3-\sqrt{2}-1}{2} =\frac{2-\sqrt{2}}{2}$

$E(1-\sqrt{2})=\frac{3-1+\sqrt{2}}{2} =\frac{2+\sqrt{2}}{2}$

$E(\sqrt{2}+1)+E(1-\sqrt{2})=\frac{2-\sqrt{2}}{2}+\frac{2+\sqrt{2}}{2}=2$

3. a) $\frac{x}{x^{2}-x}=\frac{x}{x(x-1)}=\frac{1}{x-1}$

b) 2a=3b

$\frac{2a+b}{12a-5b}=\frac{3b+b}{6*3b-5b}=\frac{4b}{13b} =\frac{4}{13}$

c) $(2x+1)^{2}-1= 2x(2x+3)-5$

$(2x+1)^{2}-2= 2x(2x+3)-5\\4x^{2} +4x+1-2=4x^{2} +6x-5\\4x^{2}-4x^{2}-1+5=6x-2x\\4=4x$ ⇒ x=1

d) (x²+4x+3)(x-1)=(x²+2x-3)(x+1)

x³+3x²+3x-3=x³+3x²-2 ⇒ x=-1

Explicație pas cu pas: