Question

For which equation is x = 9 a solution?

Answer 1

Substitute the value of x = 9 to the equations:

$A.\ 3x-7=-34\\\\L_s=3\cdot9-7=27-7=20;\ R_s=-34\\\\L_s\neq R_s\\\\B.\ x-9=1\\\\L_s=9-9=9;\ R_s=1\\\\L_s\neq R_s\\\\C.\ \dfrac{x}{9}-8=9\\\\L_s=\dfrac{9}{9}-8=1-8=-7;\ R_s=9\\\\L_s\neq R_s\\\\D.\ 4x+5=41\\\\L_s=4\cdot9+5=36+5=41;\ R_s=41\\\\L_s=R_s$

Answer: D. 4x + 5 =41

Answer 2

Answer

D. 4x + 5 = 41

 4(9) + 5 = 41
   36 + 5 = 41
        41  = 41 (TRUE)