Question

Resolva os sistemas de equações usando o método conveniente.
a) {x+y=360}
{x-y=140}

b) {x=5y}
{7x-20y=45}

c) {x+y=43}
{x-y=29}


d) {5x+2y=10}
{x+5y=110}

Answer 1

a) x+y=360
x-y=140 b) x=5y c) x+y=43 d) 5x+2y=10 x=10-2 (-20)/5
2x= 500 7x-20y=45 x-y=29 x+5y =110 x=10+40/5
x= 500/2 7x-20y=45 2x= 72 5x+2y=10 x=50/5
x= 250 7 (5y)-20y=45 x=72/2 5x=1 0-2y x=10
x+y= 360 35y-20y=45 x=36 x=10-2y/5=110-5y
250+y=360 15y=45 x+y=43 10-2y=5 (110-5y)
y=360 - 250 y=45/15 36+y=43 10-2y=550-25y
y=110 y=3 y=43-36 -2y-25y=550-10
x=5y y= 7 -27y=540 (-1)
x=5.3 27y=-540
x=15 y=-540/27
y=-20
x=10-2y/5