Answer:
Length= 19cm
Width= 9cm
Step-by-step explanation:
let the length of the rectangle be L cm and its width be W cm.
Perimeter of rectangle= 56cm
2L +2W= 56
L +W= 56 ÷2
L +W= 28
L= 28 -W -----(1)
Area of rectangle= length ×width
LW= 171 -----(2)
Susbt. (1) into (2):
W(28 -W)= 171
28W -W²= 171 <em>(</em><em>expand</em><em>)</em>
W² -28W +171= 0 <em>(</em><em>bring</em><em> </em><em>everything</em><em> </em><em>to</em><em> </em><em>one</em><em> </em><em>side</em><em>)</em>
(W -19)(W-9)= 0 <em>(</em><em>factorise</em><em>)</em>
W-19=0 or W-9=0
W= 19 or W= 9
Subst into (1):
L=28 -19 or L= 28 -9
L=9 or L= 19
Since we usually take the longer side of the rectangle to be its length, L= 19 and hence W=9.
Therefore its length is 19cm and its width is 9cm.
Answer:
Copper
Step-by-step explanation:
Count the exponents and this tells you the proton amount (atomic number)
and electron count
This is the electron configuration
Answer:
10.9
Step-by-step explanation:
Pythagoras theorem- a² + b² = c²
Since this is a right angle with each side on the right angle's length given you can use pythagoras theorem.
7² + 8.44² = c²
= 49 + 70.56 = c²
= 119.56 = c²
∴ c = √119.56
= 10.9
Write an equation
10 + 3x = 15 +2x
-2x -2x
-----------------------
10 + x (1x) = 15
-10 -10
----------------------
x = 5
cost= 25 (10 + 15)
