Make an equation system

Let Grogg's current age = x

Let Grogg's dad's current age = y

8(x-7) = y-7

5(x-3) = y-3

subtract equations from each other

8(x-7) - 5(x-3) = -4

solve for x

8x-56 - 5x+15 = -4

3x = 37

x = 37/3

plug in for y

8(37/3-7) = y-7

y = 149/3

Make an equation

x + (x+1) + (x+2) + (x+3) + (x+4) + (x+5) + (x+6) = 21*4(x+6)

(i'm assuming that when you say 21*4 you mean multiplication, but I'm a bit confused because no one writes problems like that and this does not give interger solutions)

Solving gives:

7x + 21 = 84x + 504

77x = -483

x = -483/77 ???

There must be a mistype in the problem or there is something wrong in my work, but there are no interger solutions for x.

if 21*4 were to refer to 4 then the solution would be x = 1, solving the same way.

a + ab = 250

a - ab = -240

Method 1:

Add the two equations so that the ab's cancel out to get:

2a = 10

so a = 5

Plug into equations to check:

5 + 5b = 250

1 + b = 50

b = 49

5 - 5b = -240

1 - b = -48

In both cases, b remains the same, therefore 5 works as an answer

Method 2:

Graphing (ðŸ’€ðŸ’€ðŸ’€)

(i was too lazy to graph by myself)

but yes, a = 5

Firstly add 111 to every number on the list so that the list becomes 544, 540, 536, ... , 8, 4. Then divide everything by 4 to get 136, 135, 134, ... , 1.

This list becomes 1, 2, 3, 4, ... , 135, 136. So, there are 136 numbers in this list.