D.
You need to flip the sign and second number
X≈1.5874
(Use the answer in the photo)
Answer:
£210
Step-by-step explanation:
A decrease of 30% represents 70% of the original cost.
100% represents the original cost
Divide the price by 70 to find 1% then multiply by 100 for original cost
original cost =
× 100 = 2.1 × 100 = £210
X + 5y = 1 . . . . (1)
8x - 2y = 3 . . . .(2)
Solution 1.
From (1), x = 1 - 5y
substituting for x in (2), we have:
8(1 - 5y) - 2y = 3
8 - 40y - 2y = 3
8 - 42y = 3
42y = 5
y = 5/42
x = 1 - 5(5/42) = 1 - 25/42 = 17/42.
Solution 2.
Multiply (1) by 8, to get:
8x + 40y = 8 . . . . . (3)
(3) - (2) = 40y - (-2y) = 8 - 3
42y = 5
y = 5/42
substitute for y into (3), to get:
8x + 40(5/42) = 8
8x + 100/21 = 8
8x = 8 - 100/21 = 68/21
x = (68/21)/8 = 17/42
Your answer is 8.4 X 10^7.
Hope this helped!