A-b=21
5a-2b=18
We can use substitution here. Take the first equation and solve for A. (Picking this one because it's easy)
a = 21+b
Plugin to the second equation:5(21+b)-2b=18
Simplify: 105 + 5b - 2b = 18
Simplify: 105 + 3b = 18
Subtract both sides: 3b = 18-105
Simplify: 3b = -87
Divide: b = -29
Plug back into the first: a=21+b
a = 21 - 29
a = -8
Option D
Answer:
Step-by-step explanation:
Several trig identities are involved in the proof of this. This is the order in which they are used.
- cos(2x) = cos²(x) -sin²(x)
- cos²(x) +sin²(x) = 1
- cos(x) = 1/sec(x)
<h3>Proof</h3>
Starting with the left side, we can transform it into the right side.

Answer:
The total cost of 14 onions and 16 potatoes will be £6.10
Step-by-step explanation:
Let onion be n and potato by p
20n = £3.00
1n = £3.00/20
= £0.15
25p = £6.25
1p = £6.25/25
= £0.25
The cost of 1 onion is £0.15, and 1 potato is £0.25
Then the cost of 14 onion and 16 potatoes together will given as
14n + 16p
substituting the values of n and p, we will have
14*0.15 + 16*0.25
2.1 + 4
= £6.10
12-(12 divided by z) make sure divided by is not in words :)hope it helped