Question

rezolvati in multime numerelor reale ecuatia :
3(x+5)-5(1-x)(1+x)=(x+3)la a 2 +(2x-1)la a 2+13

Answer 1

3(x+5)-5(1-x)(1+x)=(x+3)² +(2x-1)²+13

3(x+5)-5(1-x)(1+x)=(x+3)(x+ 3) +(2x-1)(2x- 1) +13

3(x+5)-5(1+ x- x- x²) =(x²+3x+ 3x+ 9) +(4x²- 2x- 2x+ 1) +13

3(x+5)-5(1- x²) =(x²+ 6x+ 9) +(4x²- 4x+ 1) +13

3x+15 -5 + 5x² = x²+ 6x+ 9  + 4x²- 4x+ 1+13

3x +10 + 5x² = 5x²+ 2x +23

3x- 2x = 23- 10

x= 13