When you write an equation in the slope-intercept form

the two coefficients m and b represent, respectively, the slope and the intercept.
So, in your case, m=1/4 and b= -7, which leads to the equation

Angle 1 and angle 2 are a linear pair, which make a sum of 180
angle 2=180-angle 1=180-70=110
A
Working:
Tan(angle)=opposite/adjacent
Tan60 = x/7root3
x=7root3 x Tan60
Enter in calculator
x=21