Tentukan nilai x dari persamaan linear satu variabel berikut
1)x+5=17
2)2x-3=12
3)x+3=2x-8
4)6x-5=2x+11
5)3(2x-1)=5(x-1)
6)x-(4-x)=3(x-4)-4
7)7x-15=6(x+2)

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.