Matematica

Equaçao do primeiro grau com duas incognitas

EXEMPLO 2:

Exemplo 2

Dada a equação x – 4y = –15, determine os pares ordenados obedecendo ao intervalo numérico –3 ≤ x ≤ 3.

x = –3
–3 – 4y = – 15
– 4y = –15 + 3
– 4y = – 12
4y = 12
y = 3


x = – 2
–2 – 4y = – 15
– 4y = –15 + 2
– 4y = – 13
4y = 13
y = 13/4

x = – 1
–1 – 4y = – 15
– 4y = –15 + 1
– 4y = – 14
4y = 14
y = 14/4 = 7/2

x = 0
0 – 4y = – 15
– 4y = – 15
4y = 15
y = 15/4

x = 1
1 – 4y = – 15
– 4y = – 15 – 1
– 4y = – 16
4y = 16
y = 4

x = 2
2 – 4y = – 15
– 4y = – 15 – 2
– 4y = – 17
4y = 17
y = 17/4


x = 3
3 – 4y = – 15
– 4y = – 15 – 3
– 4y = – 18
4y = 18
y = 18/4 = 9/2