Round to the nearest tenth

Given abcd ac=38 and ae=3x+4 find the value of x

Aline is perpendicular to another line m2= (-1/m1), where m1 is the slope of the original line and m2 is the slope of the perpendicular line. which of the following equations represents the line that passes through the point (-2,1) and is perpendicular to the line below?

David pays a 20% income tax on his $2,100 salary. how many dollars is the tax? show work