Mistake review MAX

What is the value of k if the expression 4x²-12x+k is a perfect square?

4x²=(2x)²

(2x+b)²=4x²+4bx+b²

4b=-12

b=-3 ????? OR 4x(x-3) b=-3, b²=k, k=9

b²=k, k=(-3)²

k=9

Find the exact value of |π-4|

4-π, because π - 4= -0.8 and since its negative we try the other way -(π-4) = 4 - π

The area of a rectangle with sides x and y is 47cm². The perimeter can be represented b?

A=x*y → 47=xy → x=47/y

P= 2x + 2y

P=2x +2(47/y)

P=2x+94/y

Solve

Solve

(Didn’t get it wrong, just make sure you know this)

Still got the mark for this, but remember the difference between an identity and an equation (this was an identity)

Didn’t get this wrong but I guessed the answer

Mistake: Did the quadratic equation 💀 (didn’t even try to factorise)

Make y = ____ and then sub it in

Make y = ____ and then sub it in

function is even if f(x)=f(-x)

Mistake: forgot to add a>0, also you can do this doing completing the square but discriminant is faster

Mistake: did f(2x+1) 💀

its honestly okay you didn’t get this one pookie…

find x

let m = 2^x
(2^x) - 5(2^x) + 4 ≤ 0

0<x<2

Simplify

1/3^x

Simplify

Solve x+1/x > 2

x can’t = 1, move x to the other side and square the denominator on both sides

x>0, x=/=1

Move |2x-1| to the other side and solve + and - then put on a number line

x > ¾ , x > ¼

Solve

(in ext book)