Question

3) Calcule os sistemas
c) 3x + y = 13
2x - y = 12
d) 2x + 7y = 17
5x - y = -13​

Answer 1

Resposta:

c) 3x+y=13 (l)

2x-y=12.(ll) por substituição

(l) y=13-3x

(l) em (ll)

2x-(13-3x)=12

2x-13+3x=12

5x=25.

x=5 (l) y=13-3x

y=13-15

S(5.-2) y=-2

d)2x+7y=17

5x-y=-13

-y=-13-5x. x(-1)

y=13+5x

2x+7(13+5x)=17

2x+91+35x=17

37x=-74

x=-2

y=13+5x

y=13-10

y=3

S(-2,3)