Answer:
The dimensions of the rectangle are 22cm of length and 15cm of width
Step-by-step explanation:
To solve this we first have to know the formula to calculate the area of a rectangle
a = area = 330 cm²
L = length =
w = width = L - 7cm
a = l * w
we replace with the known values
330 cm² = L * (l - 7cm)
330 cm² = L² - 7Lcm
0 = L² - 7Lcm - 330 cm²
when we have an equation like this we can use bhaskara
a = 1
b = -7Lcm
c = -330cm²
ax² + bx + c = 0
x = -b(±)√(b² - 4ac)/2a
we replace with the known values
L = -(-7cm)(±)√(7² - 4(1)(-330cm²)) / 2(1)
L = 7cm(±)√(49 + 1320cm²)) / 2
L = 7cm(±)√(1369cm²)) / 2
L1 = (7cm + 37cm) / 2
L1 = 44cm / 2 = 22cm
L2 = (7cm - 37cm) / 2
L2 = -30cm / 2 = -15cm
The positive represents the unknown with which we work (L) and the negative with which we do not work (W)
The dimensions of the rectangle are 22cm of length and 15cm of width
