Question

(3x+1)^2-5x=7+2x
Hit. nilai dari X1^2+X2^2! somebody can help me?

Answer 1

(3x + 1)² - 5x = 7 + 2x
9x² + 6x + 1 - 5x = 7 + 2x
9x² + 6x - 5x - 2x + 1 - 7 = 0
9x² - x - 6 = 0
a = 9, b = - 1, c = -6

x1 + x2 = -b/a = 1/9
x1.x2 = c/a = -6/9 = -2/3

x1² + x2² = (x1 + x2)² - 2.x1.x2
awalnya dari ini gan (x1 + x2)² = x1² + 2x1x2 + x2²
(x1 + x2)² = x1² + x2² + 2x1.x2.. lha yang dicari kan x1² + x2²
2.x1x2 pindah keruas kiri jadinya x1² + x2² = (x1 + x2)² - 2.x1.x2..gitu gan...ok?


= (1/9)² - 2(-2/3)

= 1/81 + 4/3

= 1/81 + 108/81

= 109/81

Answer 2

(3x+1)∧2  - 5x = 7+2x
9x∧2+6x+1-5x= 7+2x
9x∧2-x-6=0

x1, = (1+√1+24 ) ÷ 2x9
x1 = 6/18

x2 = (1- √1+24) ÷ 2x9
x2 = -4/18

x1∧2+x2∧2 = 36/18 + 16/18= 52/18