Question

Sa se afle nr natural X. 12(×+1)-4 (×+1)=40. 7(8-×)+3(8-×)=60. 15(×-4)-8(×-4)=21

Answer 1

12(x+1)-4(x+1)=40=> 12x+12-4x-4=40=>8x+8=40 => 8(x+1)=40=> x=5-1=4; 7(8-x)+3(8-x)=60=> 56 -7x+24-3x=60=> -10x+80=60=> -10x=-20 /*(-1)=> 10x=20=> x=2; 15(x-4)-8(x-4)=21=>15x -60-8x+32=21=>7x-28=21=> 7x=49=> x=7