Question

1)aflati nr. Natural x daca:3+6+9+.....+297=150x

2)2x{12+3x[60-3x(27-4x3)]}-5x=7. rezolva in mulțimea numerelor ecuatia

Answer 1

1) 3(1+2+3+...+99)=150x
(99×100)/2=50x
99×50=50x
99=x

2) 2×{12+3×[60-3×(27-12)]}-5x=7
2×[12+3×(60-3×15)]-5x=7
2×[12+3×(60-45)]-5x=7
2×(12+3×15)-5x=7
2×(12+45)-5x=7
2×57-5x=7
114-5x=7
5x=114-7
5x=107
x=21,4

Answer 2

2x{12+3x[60-3x(27-4×3)]}-5x=7 2x{12+3x[60-3x(27-12)]}-5x=7 2x{12+3x[60-3x15]}-5x=7 2x{12+3x[60-45]}-5x=7 2x{12+3x15}-5x=7 2x(12+45)-5x=7 2x57-5x=7 114-5x=7 5x=114-7 5x=107 x=107:5 x=21,2