noobfromvn26

Area = 7*9 + pi*(5^2/2) + 7*4 = 91 + 25/2*pi

the idea is spliting your figure to 2 rectangles and 1/2 circle.

we have equation:

25 = (1--3)^2 + (y-3)^2

solve for y, then the result of y will be 6 or 0 :)

set x = age of Mr Stevens, y = age of his grandson.

we have a set of equation:

x - y = 63

(x+3) = 4(y+3)

solve it and we have x = 81, y = 18.

About q2:

x^2 - 3x + 1 = x^2 - 2 * (3/2) * x + (9/4) - (9/4) + 1 = (x - 3/2)^2 - 5/4.

=> b = -3/2 ; c = -5/4

"the polynomial x^2+bx+c has exactly one real root" => Discriminant : b^2 - 4*a*c = 0

but a = 1 => b^2-4c = 0 (1)

we also have : b = c+1 (2)

Solve for the set of equation of (1) and (2) => c = 1.

Set x = chocolate mint, y = green mint

"The ratio of chocolate mints to green mints in a bag is 3:5" => (x/y) = (3/5) => 5x - 3y = 0 (1)

"After John ate half of the green mints and only one chocolate mint, the ratio of chocolate mint to green mint was 7:6"

=> (x - 1) / (y / 2) = (7 / 6) => 6x - (7/2)y = 6 (2)

solve the (1) and (2) as a set of equation

Then, x = 36, y = 60

Mint are left in the bag = (36 - 1) + (60/2) = 35 + 30 = 75 mints :)

Here is my solution :

https://imgur.com/a/hhC4nVl

I just used some basic geometry theories like Equilateral Triangle, Pythago, etc.

Hope it can help :)

8 / 2 * (2+2) = 8 / 2 * 4 = 4 * 4 = 16 ?

maybe just set this function equal to 6 and solve for t, the result will be two cases.

t1 nearly equal 0.57s

t2 nearly equal 2.29s

hope it can help :)

solve this equation : (93+70+99+95+x) / 5 = 90

=> x = 93.

So that She must get at least 93 for reach an A :) Hope it can help