Question

3x+x^2-5=0解方程

Answer 1

3x + x" - 5 = 0

x" + 3x + (3/2)" - 9/4 - 20/4 = 0

( x + 3/2 )" - 29/4 = 0

( x + 3/2 - √29 /2 )( x + 3/2 + √29 /2 ) = 0

( 2x + 3 - √29 )( 2x + 3 + √29 ) = 0

解方程

x1 = ( - 3 + √29 ) /2,

x2 = ( - 3 - √29 ) /2