CPhill

Good job, Brit.......

If 10^2 + 11^2 = 14^2, then we have a right triangle....so

10^2 + 11^2 = 14^2    ????

100 + 121 = 196    ???

221 = 196   ????

Nope.....no right triangle

1-sina = ctga - cosa / ctga     ???

1 - sin a   =  cos a / sin a    - cos a / (cos a / sin a)   ???

1 - sin a = cos a / sin a  - sina     add sin a to both sides

1 = cos a / sin a  ????    

Nope.......not an identity.......

"C"   looks good......rent < 3000 for Chicago   .... > 2900 for Tokyo  ......

-2<2(x-1)<3   divide everything by 2, first

-1 < x-1 < 3/2     add 1 to everything

0 < x < 5/2

In interval notation, we have

(0, 5/2 ]

No....we want everything on the same side  - I prefer the left side, myself

For instance....this one...

-(x^2) +1 = -5(x^2) + 4x        add 5x^2 to both sides and subtract 4x from both sides

4x^2 - 4x + 1 = 0      so...a = 4 b = -4 and c = 1     (got it ???)

(Actually....I wouldn"t even use the Q formula on this one....it can be factored and solved directly.....!!!.......but if that's what they're asking you to do.....)

Shadew.....let us know if you have trouble putting any of them in S.F.......once you do that....it's just "plug and play," basically.......

2x>5 or -(5/7)x-4>7

2x>5     divide both sides by 2

x > 5/2

-(5/7)x-4>7       add 4 to both sides

-5/7x > 11        multiply both sides by -7/5  and reverse the inequality sign

x < -77/5

"Or"  usually means "Union"

So....the solution set is

(-∞, -77/5) U [5/2, ∞)

This doesn't make any sense to me....... an angle of 9 degrees???.....what are you referring to???

Remember folks......just because it's easy for YOU doesn't mean it may be easy for EVERYBODY......