Question

Tìm x:

a, \(\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+\left(x+7\right)+\left(x+9\right)=75\)

b, \(\left(x+1\right)+\left(x+6\right)+\left(x+11\right)+...+\left(x+31\right)+\left(x+36\right)=288\)

Answer 1

Ta có:(x + 1)+(x+3)+...+(x+9)=75

=>5x + (1+3+...+9)=75

=>5x + 25=75

=>5x =50

=>x = 10

Answer 2

a. (x+1)+(x+3)+(x+5)+(x+7)+(x+9)=75

=>(x+x+x+x+x)+(1+3+5+7+9)=75

=>Xx5+25=75

=>Xx5=75-25

=>Xx5=50

=>x=50:5

=>x=10

b. sai đề

Answer 3

a)(x+1)+(x+3)+...+(x+9)=75

=>(x+x+...+x)+(1+3+...+9)=75

=>5x+25=75

=>5x=50

=>x=10

b)(x+1)+(x+6)+...+(x+36)=288

=>(x+x+...+x)+(1+6+...+36)=288

=>8x+296=288

Lớp 5 hình như chưa học số âm