s = 2(lw + lh + wh)
Divide each side by 2 : s/2 = lw + lh + wh
Subtract 'lh' from each side: s/2 - lh = lw + wh
Combine the 'w' terms: s/2 - lh = w(l + h)
Divide each side by (l + h): (s/2 - lh) / (l + h) = w
The best way to find out what 7 sweets cost, firstly, you should find out what one sweet would cost. You have 5 sweets, with a total cost of 30p. You should divide 30 by 5, giving you 6p per sweet. To get the cost of 7 sweets, you have to multiply 6p by 7, giving you 42p.
Therefore, the cost of 7 sweets is 42p.
Hope this helps :)
Answer:
x = 1; y = 1; z = 0
Step-by-step explanation:
First problem:
First equation minus second equation: 3y + 2z = 3 Eq. A
Second equation plus third equation: 2y + 4z = 2 Eq. B
-2 times Eq. A plus Eq. B: -4y = -4
y = 1
Substitute y = 1 in Eq. A: 3 + 2z = 3
2z = 0
z = 0
Substitute z = 0 and y = 1 in original first equation:
-2x + 2 + 0 = 0
-2x = -2
x = 1
Answer: x = 1; y = 1; z = 0
