<span>1,2x=3,6
x=3,6:1,2=3
x=3</span>
(x+4y)²- (4y-x)(x+4y) = x² + 2*x*4y + (4y)² - ( (4y)² - x²) =
F(x)=x^(-0,75)
f(81)=?
f(81)=81^(-0,75)=81^(-75/100)=81^((-25×3)/(25×4))=81^(-3/4)=3^(4×(-3/4))=3^(-3)=1/3^3=1/27=0,03703704
f(81)=81^(-0,75)=(1/27)=0,03703704
3/(X+2)-2/(X+3)=1/(X+1)
[3(X+3)-2(X+2)]/[(X+2)(X+3)]=1/(X+1)
[X+5]/[(X+2)(X+3)]=1/(X+1) ⇒ (X+5)(X+1)=(X+2)(X+3) ⇒
X²+6X+5=X²+5X+6 ⇒X=1
ПРОВЕРКА
3/(1+2)-2/(1+3)=1/(1+1) ВЕРНО