1. m^2 - 7m - 30
2. z^2 + 65z + 1000
3.x^2 - 45x + 450
4.d^2 - 33 d - 280
4 answers
The area of a rectangular field is given by the trinomial t2 – 4t – 45. The length of the rectangle is t + 5. What is the expression for the width of the field?
MathMate already did one of them for you
http://www.jiskha.com/display.cgi?id=1329964907
why not try his method for the others.
I will do the last one: d^2 - 33d - 280
280 = 56x5 , difference in factors of 33 ? no
280 = 40x7 , difference in factors of 33 ? YES
-280 = -40 x 7 , (-40) + 7 = -33
so
d^2 - 33d - 280 = (d - 40)(d + 7)
ok, your turn
Show us how you would do the other two.
http://www.jiskha.com/display.cgi?id=1329964907
why not try his method for the others.
I will do the last one: d^2 - 33d - 280
280 = 56x5 , difference in factors of 33 ? no
280 = 40x7 , difference in factors of 33 ? YES
-280 = -40 x 7 , (-40) + 7 = -33
so
d^2 - 33d - 280 = (d - 40)(d + 7)
ok, your turn
Show us how you would do the other two.
Please do not insert a new question as a reply to somebody else's question.
All you have to do is factor t^2 - 4t -45
To make it really simple, one of the factors is already given, so
t^2 - 4t - 45 = (t+5)(........)
you know it has to start with (t ......) and end in (.....-9)
so (t+5)(t-9)
does that produce a middle term of -4t ?? , YES
so we are done.
the width is t-9
All you have to do is factor t^2 - 4t -45
To make it really simple, one of the factors is already given, so
t^2 - 4t - 45 = (t+5)(........)
you know it has to start with (t ......) and end in (.....-9)
so (t+5)(t-9)
does that produce a middle term of -4t ?? , YES
so we are done.
the width is t-9
1000=2x500
1000=4x250
1000=5x200 don't none of them work
1000=4x250
1000=5x200 don't none of them work
1 answer