3/5x+2/5=7
-2/5 -2/5
3/5x = 6 3/5
/3/5. /3/5
X=11
Answer with explanation:
Given:
In Δ DEF, ∠3=∠4.
To prove:→ DE=E F
Proof:
1. ∠3=∠4------[Given]
2. →∠1 and ∠ 3 are Supplementary to each other.
(a)⇒∠1 + ∠ 3=180°
→∠2 and ∠ 4 are also Supplementary to each other.
(b)⇒∠2 + ∠ 4=180°
--------------------[Exterior sides in opposite rays]
3. From 1 , a and b
⇒∠ 1 = ∠ 2-------[Two Angles Supplementary to equal Angles are equal to each other]
4. 
If two angles of a Triangle are equal , then side opposite to these angles are equal.
Answer:
y= ? / ? x
==> y = 12/3 x
y = 4x
Step-by-step explanation:

K = 4
2/5 = (2x2)/(5x2) = 4/10 = 0.4