Question

как решить? 2 2
х = -х+20 , х + х = 56

Answer 1

$1) \: x = - x + 20 \\ \\ x + x = 20 \\ \\ 2x = 20 \\ \\ x = \frac{20}{2} = 10$

$2) \: x + x = 56 \\ \\ 2x = 56 \\ \\ x = \frac{56}{2} = 28$