Equation step-by-step:
7d + 34 = 4d + 19
7d = 4d + 19 - 34 → we take 34 to the right side of the equation
7d = 4d -15 → we solve for 19 - 34
7d - 4d = -15 → we take 4d to the left side of the equation
3d = -15 → we solve for 7d - 4d
d = -15 / 3 → we take 3 to the right side of the equation
d = -5 → we solve for -15 / 3
Hope it helped,
BioTeacher101