13. For what value of b would the following system of equations have an infinite number of solutions? 9x + 12y = 21 6x + 8y = 7b Please explain and show steps :)

Mathematics · Middle School · Tue Nov 03 2020

Answered on

For finding the value of "b"  first we wanna know which type of solutions the given equations have( infinite, many, or no solution) 

9x + 12y = 21, (here a(1)=9, b(1)=12,c(1)=21 )

 6x + 8y = 7b, (here a(2)=3, b(2)=8,c(2)=7b)

For finding the type of solutions the given equations have( infinite, many, or no solution)  we use the property 

a(1)/a(2)=b(1)/b(2)=c(1)/c(2)

Putting the values

9/6=12/8=21/7b 

3/2=3/2=3/b 

Taking one pair 

3/2=3/b 

b= 2 answer.