4/3 + 3/4
Make the denominator the same: 12
16/12 + 9/12
= 25/12
Turn that into a mixed number:
= 2 1/25
Answer:
3 a : 2 b = 6 : 1
Step-by-step explanation:
<em>
=
</em>
<em>3 ( a + b) = 5 ( a - b)
</em>
<em>3 a + 3 b = 5 a - 5 b
</em>
<em>5 b + 3 b = 5 a - 3 a
</em>
<em>
8 b = 2 a
</em>
<em>
2 a = 8 b</em>
<em><u>a = 4 b</u></em>
<em>3 a = 3 × 4 b</em>
<em><u>3 a = 12 b</u></em>
<em>3 a: 2 b = 12 b : 2 b</em>
<em>3 a : 2 b = 6 : 1</em>
Let S be the sum,
S = 2 + 4 + 6 + ... + 2 (n - 2) + 2 (n - 1) + 2n
Reverse the order of terms:
S = 2n + 2 (n - 1) + 2 (n - 2) + ... + 6 + 4 + 2
Add up terms in the same positions, so that twice the sum is
2S = (2n + 2) + (2n + 2) + (2n + 2) + ... + (2n + 2)
or
2S = n (2n + 2)
Divide both sides by 2 to solve for S :
S = n (n + 1)