Question

sistema linear utilizando método de substituição = A) 4x+4y=52 / -2x-5y=-56

B) 5x+3y=50 / 8x+5y=80

Answer 1

A) $\left \{ {{4x+4y=52} \atop {-2x-5y=-56}} \right.$

4x+4y=52 :4
x+y=13
x=13-y
x=13-10
x=3

-2(13-y)-5y=-56
-26+2y-5y=-56
-3y=26-56
-3y=-30
y=-30/-3
y=10

B) $\left \{ {{5x+3y=50} \atop {8x+5y=80}} \right.$

5x+3y=50
3y=50-5x
y=$\frac{50-5x}{3}$
y=$y=\frac{50-5*10}{3} \\ \\ y=0$

8x+5y=80
$8x+5 \frac{50-5x}{3}=80 \\ \\ 8x+ \frac{250-25x}{3}=80 \\ \\ 24x+250-25x=240 \\ \\ -x=-10 \\ \\ x=10$