Question

aflati valoare raportului algebric 0,8x+1.2y totul pe x-y):a)x=2y b)y=2x c)x pe y =1.3 d)y pe x =-0.4

Answer 1

$<span>\bold{a)} \ x=2y \to\frac{0,8x+1,2 y}{x-y}=\frac{0,8 \cdot 2y +1,2 y}{2y-y}=\frac{1,6y+1,2y}{y}=\frac{2,8\not{y}}{\not{y}}=\boxed{2,8}; \\ \\ \bold{b)} \ y=2x \to \frac{0,8x+1,2 y}{x-y}=\frac{0,8x+1,2 \cdot 2x}{x-2x} =\frac{0,8x+2,4x}{-x}=\frac{3,2\not{x}}{-\not{x}}=\boxed{-3,2}; \\ \\ \bold{c)} \ \frac{x}{y}=1,3 \Rightarrow x=1,3y \to \frac{0,8x+1,2 y}{x-y}=\frac{0,8 \cdot 1,3y+1,2 y}{1,3y-y} =$ 

$=\frac{1,04y+1,2y}{0,3y}=\frac{2,24\not{y}}{0,3\not{y}}=\boxed{\frac{2,24}{0,3}=\bold{7,4(6)}}; \\ \\ \bold{d)} \ \frac{y}{x}=-0,4 \Rightarrow y=-0,4x \to \frac{0,8x+1,2 y}{x-y}=\frac{0,8x+1,2 \cdot (-0,4y)}{x-(-0,4x)} = \\ \\ =\frac{0,8x+(-0,48x)}{x+0,4x}=\frac{0,8x-0,48x}{1,4x}=\frac{0,32\not{x}}{1,4\not{x}}=\boxed{\frac{0,32}{1,4}\approx\bold{0,23}}.$,