Find sum of all numbers divisible by 7 between 100 and 200

The numbers which are divisible by 7 between 100 and 200 are

105,112,119......,196

Since, the difference between the consecutive terms is constant. i.e.,

The first term

The common difference

The last term

Therefore the sum the terms is

Therefore, the sum of all the numbers between 100 and 200 which are divisible by 7 is 2107.

Since both equations are equal to y, we can set them equal to each other.

y =-3x +8

y = -5x -2

-3x +8 = -5x -2

Solve for x.To do this, we need to get x by itself. First, move all the numbers to one side of the equation, and all the variables to the other.

-3x +8 = -5x -2

Add 5x to both sides

-3x+5x +8=-5x+5x -2

2x+8=-2

Subtract 8 from both sides

2x+8-8 = -2-8

2x=-10

Now, all the numbers are on one side, with the variables on the other. x is not by itself, it is being multiplied by 2. To undo this, divide both sides by 2

2x/2= -10/2

x= -5

Now, to find y, substitute -5 in for x in one of the equations.

y = -5x -2

y= -5(-5) -2

y=25-2

y=23

Put the solution into (x,y)

The solution is (-5, 23)