Hi Maths lovers, if someone can explain me when l want to get NR doing NSR way ( going upwards) where this 3/5 b + 2/5 a or 2/5 a + 3/5 b comes from? Thanks

Answer:
see explanation
Step-by-step explanation:
SQ = SP + PQ = - b + a
Since SN : NQ = 3 : 2 then SQ = 3 + 2 = 5 parts , thus
SN = [tex]\frac{3}{5}[/tex] SQ = [tex]\frac{3}{5}[/tex] ( - b + a) = - [tex]\frac{3}{5}[/tex]b + [tex]\frac{3}{5}[/tex] a
Thus
NR = NS + SR
= - (- [tex]\frac{3}{5}[/tex] b + [tex]\frac{3}{5}[/tex] a) + a
= [tex]\frac{3}{5}[/tex] b - [tex]\frac{3}{5}[/tex] a + a
= [tex]\frac{2}{5}[/tex] a + [tex]\frac{3}{5}[/tex] b
Answer:
Yeah
Step-by-step explanation:
Very simple
It was said that
SN:NQ=3:2
→2SN = 3NQ
SN=SR-NR
SN=a - NR
NQ = NR - QR
NQ=NR - b
SQ = SN + NQ
Recall that SN=(3NQ)/2
SQ = (3NQ)/2 + NQ
SQ = (5/2)NQ
a - b = (5/2)(NR - b)
After simplification
NR = (2/5)a - (2/5)b +b
Factorize
NR = (2/5)a + (-2/5 + 1)b
NR = (2/5)a + (3/5)b