140 + 160(n – 2) = 180(n – 2)
140 = 20(n – 2)
140 = 20n – 40
20n = 180
n = 9
140+160*(n-2)=180(n-2)
140+160n-320=180n-360
160n-180n=-360+320-140
-20n=-180
20n=180
n=180:20
n=9
Геометрия ≠ математика!
140 + 160(n – 2) = 180(n – 2)
140 = 20(n – 2)
140 = 20n – 40
20n = 180
n = 9
140+160*(n-2)=180(n-2)
140+160n-320=180n-360
160n-180n=-360+320-140
-20n=-180
20n=180
n=180:20
n=9
n=9
Геометрия ≠ математика!