3f+3=t
s=2f
21=f+s+t
21=f+(2f)+(3f+3)
21=6f+3
18=6f
3=first
6=second
12=third
So Length * Width = 480 in. sq.
L=1 1/5 or 1.2W
substitute the L for 1.2W
1.2W*W=480 in sq
divide both sides by 1.2
w*w= 400
W²=400
square root of both sides
Width = 20 inches
Length= (1.2width) or (20*1.2)
Length=24 inches
To factor,
<h2>
[[[</h2>
1) First multiply coefficient of a² and constant no,
That is,
3×(-42)=-126
Since the<u> resultant no is negative</u>, you should find two such factors of 126 <u>which</u> <u>will give us the coefficient of a (=11)</u> on subracting those factors.
2) Find the factor
126=2×3×3×7
=18×7
18 and 17 are factors of 126
Also,18-7 =11.
So they are required factors for factoring,
<h2>
]]]</h2>
Once you have understood above steps you can solve on your own. All you need to do is split 11 into factors ,take common terms and you will get answer.
<u>Answer:</u>
3a²+11a-42
=3a²+(18-7)a -42
=3a²+18a-7a-42
=3a(a+6) -7(a+6)
=(a+6)(3a-7)