Question

resolva:

a) { x + y = 20
{ 5x - 3y = 4

b) { x + y = 18
{ 4x + 2y = 56

c) { x + y = 45
{ 4x + 2y = 130

d) { x + y = 27
{ 2x + 3y = 69​

Answer 1

a)

{x+y=20

{5x-3y=4

X=20-Y

5X-3Y=4

5.(20-Y)-3Y=4

100-5Y-3Y=4

-8Y= 4-100

-8Y= -96 .(-1)

8Y= 96

Y= 96/8

Y= 12

X= 20-Y

X= 20-12

X= 8

S{12,8}