3x-7>8 and -3x ≥-36 solve the inequality
Mathematics · Middle School · Mon Jan 18 2021
Answered on
Visualize as if the inequality symbols are equal signs and then solve it as you would for a normal equation, note if you divide by two negative numbers at all you then switch the sign.
On a number line, an inequality sign without the “equal to” is plotted with an open circe.
An inequality sign, with the “equal to” is plotted with a closed circle.
3x - 7> 8
Add seven on both sides, we do this because we want to eliminate the 7 from one side.
3x > 15
Divide both sides by 3, we do this because you want to get rid of the 3 from x.
x > 5
As for the second inequality.
Divide both sides by -3, as I mentioned earlier switch the side since we are dividing by two negative numbers.
x ≤ 12
For the greater than inequality x > 5, plot a open circle on 5 and draw the line going to the right.
For the less than or equal to inequality x ≤ 12, plot a closed cirlce on 12 and draw the line going to the left.
A unique trick is to graph the line based on the direction (right or left) the inequality symbol is pointing to.
Answer:
x > 5
x ≤ 12