A superb review of algebra basics; essential to retain what some of us learned back just before the last Ice Age.

Many parents and “old” people might have had poor quality teaching when they were taught math, so I share this channel with my mom and others who are “bad” at math.

got it in about 45 sec. good one, thanks. it was fun.

9”x21” (figured out in my head in less than a minute)

Width is 9; length is 21.

Greetings. The dimensions are 9 units for the width and 21 units for the length. We Shall assume that the width of the rectangular figure is X. When the width is X units, the length is 3 more than twice this measure. Therefore, the length is (2X +3) units. Moving forward, the perimeter using the dimensions is 2(X+ 2X+3)=2(3X+3)=6X+6 units. We will now equate the values of the perimeters to get 6X+6=60, and 6X=60-6, 6X=54 and X=54/6 =9 units, the width of rectangular figure. The length is twice the value of X +3 = (2×9+3)=18+3=21 units.

The perimeter (2 eidths + 2 lengths) is 6x +6 =60 if the width ix x & one of the long sides is 2x+2. This makes it easy to solve since every term is divisible by 6, such that x+1=10 making x=9

Took a few tries. But the length is 21 and the width is 9. 2L + 2W = 60 L = length. W = width. P = perimeter. L = 2W + 3 2(2W + 3) + 2W = 60 4W + 6 + 2W = 60 6W + 6 = 60 6W = 54 W = 9 L = 2W + 3 L = 2(9) + 3 L = 18 + 3 L = 21 Therefore 21x9 rectangle. 2L + 2W = 60. 2(21) + 2(9) = 60 42 + 18 = 60 60 = 60 😊

Known: L = 2W +3 P = 60 2L + 2W = P 2L +2W = 60 Solve: Substitute (2W + 3) for L 2 (2W+3) + 2W = 60 Distributive property 2*2W + 2*3 + 2W = 60 4W + 6 + 2W = 60 6W + 6 = 60 Subtract 6 on both sides 6W = 60 - 6 6W = 54 Divide by 6 on both sides W = 9 Solve for L L = 2*9 +3 L = 18 + 3 L = 21

Thank you. What software are you using for this video (for writing), can you tell me, please?

If we call the width X that would make the length 2X + 3 and we have been told that 2X + 2(2X + 3) = 60 do the 2(2X + 3) 2X + 4X + 6 = 60 add the Xs together 6X + 6 = 60 subtract 6 from both sides 6X = 54 divide both sides by 6 X = 9 The width is 9 and the length is 9 x 2 + 3 = 21 and to check 9 + 9 + 21 + 21 = 60

Dim 21*9

21 and 9

9x21

9 and 22

9 × 21

9 x 21. Let X equal the width.

two equations in two unknowns L W eq.1: 2L + 2W = 60 eq.2: L = 2W + 3 modifying eq.2 and then putting into eq.1 => eq.2: L = 2W + 3 2W = L - 3 eq.1: 2L + 2W = 60 2L + (L - 3) = 60 3L = 63 L = 21 from eq.2 eq.2: L = 2W + 3 21 = 2W + 3 18 = 2W W = 9 VERIFY: L=21, W=9 from eq.1 eq.1: 2L + 2W = 60 2(21) + 2(9) =? 60 42 + 18 =? 60 60 =❤ 60✔️

@terry_willis

7 ай бұрын

Why use 2 unknowns when 1 will work?

@tomtke7351

7 ай бұрын

@@terry_willis both length and width are unknowns

21 ×9

Trick question

Width-9 Length-21

Length = 21 Width = 9

Length is 22.5 Width is 7.5

@kevinmcguinness1113

7 ай бұрын

Not correct - read the question again.

Width=9cm Length=21cm

I liked it until you took 2 minutes to ask us to like it... 😞

I got this wrong.

17 minutes to explain this? Seriously? It took me 40 seconds to solve this in my head. You must be the most boring math teacher ever.

21 and 9