Answer:
Q 10. infinite solutions (S)
Q 11. no solution (O)
Q 12. no solution (P)
Q 13. one solution (E)
Q 14. no solution (O)
Explanation:
Q 10.
3(x+1)-4x = 3(2x+1)-7x
3x+3-4x = 6x+3-7x
-x+3 = -x+3
x = x
It is an identity (Left Right completely the same)
so infinite solutions
Q 11.
(6x+8)/2-x = 2x+8
3x+4-x = 2x+8
2x+4 = 2x+8
x+2 = x+4
no real solution for this equation (x+2 not equal to x+4 for any real x)
Q 12.
7x+3-3x = 4(x-2)
4x+3 = 4x - 8
x +3/4 = x-2
again no real solution
Q 13.
-6(x-2) = -7(x-3)
-6x+12 = -7x+21
x = 9
one solution
Q 14.
-0.7x+0.5+1.2x = 0.5x+0.8
0.5x+0.5 = 0.5x+0.8
x+1 = x+1.6
no real solution