2 Answers

CDahn · Answer 1 · 2019-02-07T18:52:31+0000

Answer:

The equation which has no solution is:

Option: C

c)
7y+9=7y-6

The equation is said to have a no solution if we get a false identity on solving the equation.

a)

5m-6=5m+7-m

On combining the like terms in the right hand side of the equation we have:

$5m-6=5m-m+7\\\\5m-6=4m+7\\\\5m-4m=7+6\\\\m=13$

Hence, we get a unique solution to the equation.

b)

3w+4-w=5w-2(2w-2)

on using the distributive property in the right hand side of the equation we have:

$3w+4-w=5w-2* w-2* (-2)\\\\3w-w+4=5w-2w+4\\\\2w+4=3w+4\\\\3w-2w=4-4\\\\w=0$

Again we get a unique solution to the equation.

c)

7y+9=7y-6

on subtracting 7y from both the sides of the equation we have:

$7y-7y-6=9\\\\-6=9$

which is a false identity.

Hence, the equation has no solution.

d)

$4z+8=-4z-2\\\\i.e.\\\\4z+4z=-2-8\\\\8z=-10\\\\z=(-10)/(8)\\\\z=(-5)/(4)$

This equation has a unique solution.