Answer:
Perimeter = 10x+8 cm
If x=4 P = 48cm
Area = 6x^2 +5x-21 cm^2
If x=4 A = 95 cm^2
Perimeter of new blanket is =10x+18 cm
Step-by-step explanation:
Perimeter = 2(l+w)
= 2( 3x+7 + 2x-3)
Combine terms
= 2(5x+4)
Distribute
= 10x+8 cm
Let x = 4
P = 10*4 +8
= 40+8
=48 cm
A = l*w
= (3x+7) (2x-3)
FOIL
first: 3x*2x =6x^2
outer: 3x*(-3) = -9x
inner: 7*2x = 14x
last = 7*-3 = -21
Add together = 6x^2 -9x+14x -21
=6x^2 +5x-21 cm^2
If x=4
A = 6 (4)^2 +5(4) -21
=6*16 +20-21
=96+20-21
= 95 cm^2
New blanket with length 5 cm longer
Perimeter = 2(l+w)
l = 3x+7+5
l = 3x+12
= 2( 3x+12 + 2x-3)
Combine like terms
=2(5x+9)
Distribute
=10x+18 cm
