A pack of pencils is on sale at Office Pro for $2.96. You want to purchase 5 packs. Can you use mental math to
calculate the total cost before taxes? “Mental math" means
trying to do this without writing anything, and without
consulting a calculator. Be prepared to explain your
solution method.

$14.80

Step-by-step explanation:

Round 2.96 up to 3. 3*5=15. 3-2.96=0.04. 0.04*5=0.2. 15-0.2=14.8.

Yes you can. Your answer is 14.80

Step-by-step explanation:

I would first do 5 times $3.00 which would equal $15.00. Then take the four cents that I added to make it 3 dollars and subtract it from $15. 0.04 times 5 equals 0.20. Then $15.00 minus 0.20 equals $14.80

your answer would be 12

let's call the solutions x₁ = (5 - 2√7)/3 and x₂ = (5 + 2√7)/3

then the equation is (x-x₁)(x-x₂) = 0

if you fill that in you get a lot of numbers which you can recognize as ax²+bx+c=0.

step-by-step explanation:

you can see that a=1 (there is just an x²)

b = (-5 -2√7 + 2√7 - 5)/3 = -10/3

c = -2√7)/3 ) * (-5+2√7)/3) = -1/3

so your answer is 3x^2 – 10x – 1 = 0