Question

Va rog mult!!! Dau 100 de puncte și coroana
Nu ma pricep la mate plssss
Toată pagina plssss​

Answer 1

Răspuns:

20.

L₁/L₂ = 3/2

l₁/l₂ = 4/5

A₁/A₂ = (L₁ ×l₁)/(L₂×l₂)

A₁/A₂ = L₁/L₂ × l₁/l₂

A₁/A₂ = 3/2 × 4/5

A₁/A₂ = 12/10

A₁/A₂ = 6/5

19.

P₁/P₂ = 2/5

4l₁/4l₂ = 2/5

l₁/l₂ = 2/5

l₁²/l₂² = 2²/5²

A₁/A₂ = 4/25

18.

A₁/A₂ = 121/289

l₁²/l₂² = 11²/17²

l₁/l₂ = 11/17

P₁/P₂ = 4×11/4×17

P₁/P₂ = 44/68

P₁/P₂ = 11/17

17.

(2x+y)/(5x-y) = 5/2

4x+2y=25x-5y

25x-4x=2y+5y

21x=7y

3x=y

y=3x

a. (17x+y)/(13x+4y) =

=(17x+3x)/(13x+4×3x)

=(20x)/(13x+12x)

=20x/25x

=20/25

=4/5

b. (y²+4xy+x²)/(y²+2xy-4x²)=

=[(3x)²+4×x×3×x+x²]/[(3x)²+2×x×3×x-4x²]

=(9x²+12x²+x²)/(9x²+6x²-4x²)

=22x²/11x²

=22/11

=2

16.

(2a+b)/5=(5a-b)/2

4a+2b=25a-5b

25a-4a=2b+5b

21a=7b

3a=b

b=3a

a.

(7a+,b)/(13a-4b)=

=(7a+3a)/(13a-4×3a)

=(10a)/(13a-12a)

=10a/1a

=10

b.

(b²+6ab+a²)/(b²+2ab-a²)=

=[(3a)²+6×a×3×a+a²]/[(3a)²+2×a×3×a-a²]

=(9a²+18a²+a²)/(9a²+6a²-a²)

=28a²/14a²

=28/14

=2

15.

(6x+5y)/(2x+4y)=8/5

30x+25y==16x+32y

30x-16x=32y-25y

14x=7y

2x=y

y=2x

y/x=2x/x=2

(4xy-x²)/(y²-xy)=

=(4×x×2×x-x²)/[(2x)²-x×2×x]

=(8x²-x²)/(4x²-2x²)

=7x²/2x²

=7/2

14.

(4x+y)/22=(5x-y)/14

(4x+y)/11=(5x-y)/7

28x+7y=55x-11y

55x-28x=7y+11y

27x=18y

3x=2y

y=3/2 × X

(3x+2y)/(5x-2y)

3x+2y=3x+2×3/2 × X =

=3x+3x=6x

5x-2y=5x-2×3/2 × X =

=5x-3x=2x

(3x+2y)/(5x-2y)=

=6x/2x=6/2=3

13.

(13x-7y)/5y=1/3

39x-21y=5y

39x=5y+21y

39x=26y / :13

3x=2y

y= 3/2 × x

x/y=x / 3/2x =

=1/ 3/2 = 1× 2/3 =2/3

(x²+y²)/x²

x²+y²=x²+(3/2x)²=

=x²+(9/4)x²

=(4x²+9x²)/4

=(13/4) × x²

(x²+y²)/x²=

=(13/4) × x² /x²

=13/4