Answer to Question #153887 in Algebra for Diana

Question

the inequality x+c>-2.55 has the solution x>4.85. What is the value of c? How do you know?

Answer 1

$x+c>-2.55$

Subtracting $c$ from both sides of the inequality, we get:

$x+c-c>-2.55-c$

$x>-2.55-c$

Since $x>4.85$ is the solution, we conclude that $-2.55-c=4.85$ .

Add $c$ to both sides of the equality:

$-2.55-c+c=4.85+c$

$-2.55=4.85+c$

Subtract $4.85$ from both sides of the equality:

$-2.55-4.85=4.85+c-4.85$

$-7.4=c$

Answer: $c=-7.4$ .