Question

5. Raportul masurilor a doua unghiuri complementare este 1/5. Afla masurile unghiilor :
6. Daca 2x/ pe 3/y =1/2 calculeaza
a) x/y =
b) 2x-y pe x+y

Answer 1

1.Noi stim ca suma a doua unghiuri complementare= 90 grade
Respectiv , putem nota unghiul 1 = x , al doilea 5x , dupa caz.
x+5x=90
6x=90
x=90:6
x=15 grade , deci primul unghi are 15 grade
5x=15x5=75 , deci al doilea =75 grade

2. a).2x/3y=1/2
2x=3y/2
x=3y/2/2
x=3y/2x1/2
x=3y/4
x/y=  3y/4/y=  3y/4 * 1/y=  3/4
x/y=3/4

b) 2x-y)/(x+y)=  (2* 3y/4 -y) / (3y/4+y)=
=( 3y/2 -y) / (3y/4 +y)   Se aduce la acelasi numitor , asadar :
= (3y-2y)/2 / (3y+4y)/4=
= y/2 /7y/4=
=y/2 * 4/7y= 2/7

Answer 2

5) Algebra:
a+b=180
a:b=5
a=5b
5b+b=180
6b=180
b=180:6
b=30
a=30x5
a=150
Metoda grafica:
a+b=180
a:b=5
a=5b
a I_I_I_I_I_I
b I_I acolada 180
180:6=30(b)
30x5=150(a)
6)
2x:3y=1:2
2x=3y:2
x=3y:2:2
x=3y:x1:2
x=3y:4
a)
x:y=3y:4:y=3y:4x1:y=3:4
x:y=3:4
b)
(2x-y):(x+y)=(2x3y:4-y):(3y:4+y)=
=(3y:2-y):(3y:4+y) aducem la acelasi numitor
=(3y-2y):2:(3y+4y):4=
=y:2:7y:4=
=y:2x4:7y=2:7