$${a\over b}={2\over3}$$ and $${b\over c}={4\over5}$$ then the ratio  $${a+b}\over {b+c}$$ equal to:

$${3x+4y-2z+9=17},{7x+2y+11z+8=23}$$ and $$ {5x+9y+6z-4=18}$$ then what is  the value of $$ {x+y+z-34}$$?

(x+2y) (x² + 4y² – 2xy) equal to- 

If $$ {P={96\over95×97}},{Q={97\over96×98}}$$ and $$ {R={1\over97}}$$ then which of the following is True?

If a+b=2c, find $${a\over a-c}+{c\over b-c}?$$

If then the value of

If a+b=17,and a – b =9, then the value of $$ {(4a^2+4b^2)}$$ is:

If (a-b)² + (b-c)² + (c-a)² = 0, then find the value of (a³+b³+c³-3abc) ?