Candles normally cost £6 each. Two websites have special offers
Corbettmaths Candles
Candles'R'us
Buy 3 get 1 free
20% off
Laura wants to buy 30 candles.
Which website should Laura use?

the least common denominatore of 7 and 2 is 9

step-by-step explanation:

7+2=9

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

step-by-step explanation:

x-intercept:

(

−

1

+

√

7

,

0

)

,

(

−

1

−

√

7

,

0

)

y-intercept:

(

0

,

−

6

)