Question

resolver la siguiente ecuación por eliminación o sustitución: a-8b= -9 a-2b= -7

Answer 1

Answer: Solution: $a=\dfrac{-19}{3}$ and $b=\dfrac{1}{3}$ .

Step-by-step explanation:

The given pair of equations:

$a-8b= -9\ ...(i)\\\\ a-2b= -7\ ...(ii)$

Eliminate equation (i) from (ii) , we get

$-2b-(-8b)=-7-(-9)\\\\\Rightarrow\ -2b+8b=-7+9\\\\\Rightarrow\ 6b=2\\\\\Rightarrow\ b=\dfrac{1}{3}$

Put value of b in (ii) , we get

$a-2\times\dfrac{1}{3}=-7\\\\\Rightarrow\ a=-7+\dfrac{2}{3}\\\\\Rightarrow\ a=\dfrac{-21+2}{3}\\\\\Rightarrow\ a=\dfrac{-19}{3}$

Solution: $a=\dfrac{-19}{3}$ and $b=\dfrac{1}{3}$ .