Answer:
A= x=5 or x=-2
Step-by-step explanation:
x^2-3x-10=0
Factor
What 2 numbers multiply together to give you -10 and add together to give you -3
-5*2 = -10
-5+2 = -3
(x-5) (x+2) =0
Using the zero product property
x-5 =0 x+2 =0
x-5+5=0+5 x+2-2=0-2
x=5 x=-2
Answer:
5.5
Step-by-step explanation:
√30, which will round to 5.5, because √30*√30=30.
18×4=72=4 hats
26-18=8=1 poster
8+8+72=88=4 hats and 2 posters
72=4 hats
72÷4=18= 1 hat costs $18
16÷2=8= 1 poster costs $8
Cos²x+2cos x+1=0
We have to do a change of variable.
cos x=t
Then, we have the next square equation.
t²+2t+1=0
We solve this square equation:
t=[-2⁺₋√(4-4)]/2=-1
if cos x=t then we have that:
cos x=-1
x=cos⁻¹ -1= π radians or 180º.
Answer: x=π (in radians) or x=180º (in degrees).