Question

regra de cramer 2x+5y=8 x+y=7

Answer 1

O meu resultado deu 1 e -1. Mas só bate com uma equação :/

Answer 2

$D = \left[\begin{array}{ccc}2&5\\1&1\\\end{array}\right] = 2 - 5= -3; D_{x} = \left[\begin{array}{ccc}8&5\\7&1\\\end{array}\right] = 8 - 35 = -27;$$D_{y} = \left[\begin{array}{ccc}2&8\\1&7\\\end{array}\right] = 14 - 8 = 6;--\ \textgreater \ x = \frac{ D_{x} }{D} = \frac{-27}{-3} --\ \textgreater \ x = 9;$$--\ \textgreater \ y = \frac{ D_{y} }{D} = \frac{6}{-3} --\ \textgreater \ y = - 2;$