Answer:
x = 2±sqrt(11)
Step-by-step explanation:
x^2 -4x - 7 =0
Add 7 to each side
x^2 -4x -7+7 =0+7
x^2 -4x =7
To complete the square take the coefficient of the x term and divide by 2 and then square it. Add it to both sides
-4 /2 = -2 then square
(-2)^2 = 4
Add 4 to both sides
x^2 -4x+4 =7+4
x^2 -4x+4 = 11
Factor the left side into (x-b/2)^2
(x-2)^2 =11
Take the square root of each side
sqrt((x-2)^2) =±sqrt(11)
x-2 = ±sqrt(11)
Add to to each side
x-2+2 = 2±sqrt(11)
x = 2±sqrt(11)
Answer:
56.6m to 1.d.p
Step-by-step explanation:
circumference=2πr
=2×3.142×9
=56.556m
=56.6m to 1.d.p
Answer:
x=65
Step-by-step explanation:
Step 1: Add -3 to both sides.
√x−1+3+−3=11+−3
√x−1=8
Step 2: Solve Square Root.
√x−1=8
x−1=82(Square both sides)
x−1=64
x−1+1=64+1(Add 1 to both sides)
x=65
Check answers. (Plug them in to make sure they work.)
x=65(Works in original equation)
Answer:
-3mn
Step-by-step explanation:
It seems you might be missing some of the question, as you haven't given what m and n are equal to.
If the question has just given you x, then you would simply just simplify it to get -3mn.
