What error was made?

-4(6 - b) = 4
-24 - 4b = 4
-4b = 28
b = -7

If 3x+8=3x+8 is it one solution or no solution

The marked price of an article is 25% above its selling price and the cost price is 30% less than its marked price . find the discount percent and gain percent. only a brainlest can solve it i will mark you brainlest

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?