Question

Решите уравнение формулой Крамра
3x+4y=253
y-5x=0

Answer 1

$left { {{3x+4y=253} atop {-5x+y=0}} right. \\\Delta = left|begin{array}{cc}3&4\-5&1end{array}right|=3cdot 1-4cdot (-5)=3+20=23ne 0\\\Delta _1= left|begin{array}{cc}253&0\4&1end{array}right|=253\\\Delta _2= left|begin{array}{cc}3&-5\253&0end{array}right|=3\\\x= frac{Delta _1}{Delta }= frac{253}{23}=11\\\y= frac{Delta _2}{Delta }=frac{3}{23}$