The teacher will be very surprised to see your correct solution 😉
5 4 3 2 - x + 8*x - 22*x + 28*x - 24*x + 16 = 0
sum
________________ / ________________ \ ________________ / ________________ \ / _____ | / _____ | / _____ | / _____ | / 82 2*\/ 159 | ___ / 82 2*\/ 159 | / 82 2*\/ 159 | ___ / 82 2*\/ 159 | ________________ 3 / -- + --------- | \/ 3 *3 / -- + --------- ___ | 3 / -- + --------- |\/ 3 *3 / -- + --------- ___ | / _____ 4 5 \/ 27 9 | \/ 27 9 5*\/ 3 | 4 5 \/ 27 9 | \/ 27 9 5*\/ 3 | 4 / 82 2*\/ 159 10 2 + - - ----------------------- - --------------------- + I*|- --------------------------- + -----------------------| + - - ----------------------- - --------------------- + I*|--------------------------- - -----------------------| + - + 3 / -- + --------- + ----------------------- 3 ________________ 2 | 2 ________________| 3 ________________ 2 | 2 ________________| 3 \/ 27 9 ________________ / _____ | / _____ | / _____ | / _____ | / _____ / 82 2*\/ 159 | / 82 2*\/ 159 | / 82 2*\/ 159 | / 82 2*\/ 159 | / 82 2*\/ 159 9*3 / -- + --------- | 9*3 / -- + --------- | 9*3 / -- + --------- | 9*3 / -- + --------- | 9*3 / -- + --------- \/ 27 9 \ \/ 27 9 / \/ 27 9 \ \/ 27 9 / \/ 27 9
=
/ ________________ \ / ________________ \ | / _____ | | / _____ | | ___ / 82 2*\/ 159 | | ___ / 82 2*\/ 159 | |\/ 3 *3 / -- + --------- ___ | | \/ 3 *3 / -- + --------- ___ | | \/ 27 9 5*\/ 3 | | \/ 27 9 5*\/ 3 | 6 + I*|--------------------------- - -----------------------| + I*|- --------------------------- + -----------------------| | 2 ________________| | 2 ________________| | / _____ | | / _____ | | / 82 2*\/ 159 | | / 82 2*\/ 159 | | 9*3 / -- + --------- | | 9*3 / -- + --------- | \ \/ 27 9 / \ \/ 27 9 /
product
/ ________________ / ________________ \\ / ________________ / ________________ \\ | / _____ | / _____ || | / _____ | / _____ || | / 82 2*\/ 159 | ___ / 82 2*\/ 159 || | / 82 2*\/ 159 | ___ / 82 2*\/ 159 || / ________________ \ | 3 / -- + --------- | \/ 3 *3 / -- + --------- ___ || | 3 / -- + --------- |\/ 3 *3 / -- + --------- ___ || | / _____ | |4 5 \/ 27 9 | \/ 27 9 5*\/ 3 || |4 5 \/ 27 9 | \/ 27 9 5*\/ 3 || |4 / 82 2*\/ 159 10 | 2*|- - ----------------------- - --------------------- + I*|- --------------------------- + -----------------------||*|- - ----------------------- - --------------------- + I*|--------------------------- - -----------------------||*|- + 3 / -- + --------- + -----------------------| |3 ________________ 2 | 2 ________________|| |3 ________________ 2 | 2 ________________|| |3 \/ 27 9 ________________| | / _____ | / _____ || | / _____ | / _____ || | / _____ | | / 82 2*\/ 159 | / 82 2*\/ 159 || | / 82 2*\/ 159 | / 82 2*\/ 159 || | / 82 2*\/ 159 | | 9*3 / -- + --------- | 9*3 / -- + --------- || | 9*3 / -- + --------- | 9*3 / -- + --------- || | 9*3 / -- + --------- | \ \/ 27 9 \ \/ 27 9 // \ \/ 27 9 \ \/ 27 9 // \ \/ 27 9 /
=
8
8
x1 = 2
________________ / ________________ \ / _____ | / _____ | / 82 2*\/ 159 | ___ / 82 2*\/ 159 | 3 / -- + --------- | \/ 3 *3 / -- + --------- ___ | 4 5 \/ 27 9 | \/ 27 9 5*\/ 3 | x2 = - - ----------------------- - --------------------- + I*|- --------------------------- + -----------------------| 3 ________________ 2 | 2 ________________| / _____ | / _____ | / 82 2*\/ 159 | / 82 2*\/ 159 | 9*3 / -- + --------- | 9*3 / -- + --------- | \/ 27 9 \ \/ 27 9 /
________________ / ________________ \ / _____ | / _____ | / 82 2*\/ 159 | ___ / 82 2*\/ 159 | 3 / -- + --------- |\/ 3 *3 / -- + --------- ___ | 4 5 \/ 27 9 | \/ 27 9 5*\/ 3 | x3 = - - ----------------------- - --------------------- + I*|--------------------------- - -----------------------| 3 ________________ 2 | 2 ________________| / _____ | / _____ | / 82 2*\/ 159 | / 82 2*\/ 159 | 9*3 / -- + --------- | 9*3 / -- + --------- | \/ 27 9 \ \/ 27 9 /
________________ / _____ 4 / 82 2*\/ 159 10 x4 = - + 3 / -- + --------- + ----------------------- 3 \/ 27 9 ________________ / _____ / 82 2*\/ 159 9*3 / -- + --------- \/ 27 9
x4 = 10/(9*(2*sqrt(159)/9 + 82/27)^(1/3)) + 4/3 + (2*sqrt(159)/9 + 82/27)^(1/3)
x1 = 3.75110070237603
x2 = 0.124449648811983 + 1.02511753217493*i
x3 = 0.124449648811983 - 1.02511753217493*i
x4 = 2.0
x4 = 2.0