Question

Calcule os sistemas a)
10x+10y=20 e 2x+y=1
b)3x+3y=90 e 5x+3y=54
c)x+y=30 e 5x+3y=54

preciso do calculo urgentee por favoor​

Answer 1

Mamão com açúcar!

a) {10x+10y=20 ÷10

{2x+y=1

{x+y=2×(-1)

{2x+y=1

{-x-y=-2

+{2x+y=1

$2x - x = - 2 + 1 \\ x = - 1$

$x + y = 2 \\ - 1 + y = 2 \\y = 2 + 1 \\ y = 3$

S={–1,3}

b)

{3x+3y=90÷3

{5x+3y=54

{x+y=30 ×(-3)

{5x+3y=54

{-3x-3y=-90

+{5x+3y=54

$5x - 3x = - 90 + 54 \\ 2x = - 36 \\ x = - \frac{36}{2} \\ x = - 18$

$x + y = 30\\ - 18 + y = 30 \\ y = 30 + 18 \\ y = 48$

S={–18,48}

c)

{x+y=30

{5x+3y=54

{x+y=30 ×(-3)

{5x+3y=54

{-3x-3y=-90

+{5x+3y=54

$5x - 3x = - 90 + 54 \\ 2x = - 36 \\ x = - \frac{36}{2} \\ x = - 18$

$x + y = 30\\ - 18 + y = 30 \\ y = 30 + 18 \\ y = 48$

S={–18,48}