Question

a)5x-y=1
x+y=5
b)x-y=2
3x+y=14
No método de substituição

Answer 1

Resposta:

a) x = 1 & y = 4

b) x = 4 & y = 2

Explicação passo-a-passo:

x+y=5

x = 5 - y

5x - y = 1

5.(5-y) - y = 1

25 - 5y - y = 1

25 - 6y =1

25 - 1 = 6y

24/6 = y

y = 4

x = 5 - y

x = 5 - 4

x = 1

x-y=2

x = 2 + y

3x+y=14

3(2+y) + y = 14

6 + 3y + y = 14

6 + 4y = 14

4y = 14 - 6

y = 8/4

y = 2

x = 2 + y

x = 2 + 2

x = 4

Answer 2

$\Large\boxed{\boxed{\boxed{{Ola\´\ }}}}}$

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a)

$\sf\left \{ {{5x - y=1} \atop {x + y=5}} \right. \\ \\ \sf\left \{ {{5x - y=1} \atop { y=5 - x}} \right. \\ \\ \sf5x - y = 1 \\ \sf5x - (5 - x) = 1 \\ \sf5x - 5 + x = 1 \\ \sf6x - 5 = 1 \\ \sf6x = 1 + 5 \\ \sf6x = 6 \\ \sf x = \frac{6}{6} \\ \large\boxed{{\sf \large\boxed{{\sf x =1 {}}}{}}} \\ \\ \\ \sf \: y = 5 - x \\ \sf y = 5 - 1 \\ \large\boxed{{\sf \large\boxed{{\sf y = 4{}}}{}}}$

b)

$\sf\left \{ {{x - y=2} \atop {3x + y=14}} \right. \\ \\ \sf\left \{ {{x - y=2} \atop { y=14 - 3x}} \right. \\ \\ \sf x - y = 2 \\ \sf x - (14 - 3x) = 2 \\ \sf x - 14 + 3x = 2 \\ \sf4x - 14 = 2 \\ \sf4x = 2 + 14 \\ \sf4x = 16 \\ \sf x = \frac{16}{4} \\ \large\boxed{{\sf \large\boxed{{\sf x =4 {}}}{}}} \\ \\ \\ \sf \: y = 14 - 3x \\ \sf y = 14 - 3.4 \\ \sf y = 14 - 12\\ \large\boxed{{\sf \large\boxed{{\sf y = 2{}}}{}}}$