The correct option is D 5x+7=x−1
To solve multi-step equations, you need to solve more than two mathematical operations to find the solution of an equation.
(A) x−3=0
Add 3 to both the sides
x−3+3=0+3⇒x=3
∴ It took only one step to solve the equation. So, it is an one step equation.
(B) 6x−18=0
Add 18 to both the sides
6x−18+18=0+18
⇒6x=18
Divide both the sides by 6
6x6=186
⇒x=3
∴ It took two steps to solve the equation. So, it is a two step equation.
(C) x+3=x2−1
Subtract both the sides by x2
x+3−x2=x2−1−x2
x2+3=−1
Subtract both the sides by 3
x2+3−3=−1−3
⇒x2=−4
Multiply both the sides by 2
x2×2=−4×2
⇒x=−8
∴ It took three steps to solve the equation. So, it is a multi step equation.
(D) 5x+7=x−1
Subtract both the sides by x
5x+7−x=x−1−x
⇒4x+7=−1
Subtract both the sides by 7
4x+7−7=−1−7
⇒4x=−8
Divide both the sides by 4
4x4=−84
⇒x=−2
∴ It took three steps to solve the equation. So, it is a multi step equation.