Question

Como resolver?
a) X²+X.(2X-45)=0

b)3x.(x+2)+(x-1)²=x+1

obg! :)

Answer 1

a) X²+X.(2X-45)=0
x² + 2x² - 45x = 0
3x² - 45x = 0 ÷ 3
x² - 15x = 0
x.(x - 15) = 0
x = 0
x - 15 = 0
x = +15

S[0 ; 15]


b)3x.(x+2)+(x-1)²=x+1
3x² + 6x + (x² -2x +1) = x + 1
3x² + 6x + x² - 2x + 1 - x - 1 = 0
3x² +x² -2x -x + 6x +1 -1 = 0       elimina  +1 -1
4x² -3x +6x = 0
4x² + 3x = 0
x.(4x + 3) = 0
x = 0
4x + 3 = 0
4x = -3
x = -3/4

S[-3/4 ; 0]