Question

liams strategy
liam used this tape diagram and equation to represent his situation. here is his first step.
what equation would represent his new tape diagram?
the original equation is 4 + 3x = 25, and there is a tape diagram with some markings (the original tape diagram has a part marked 4, three parts marked x, and the total is 25; then there is a new marking of 21 and 25 related to the tape diagram).

Explanation:

Step1: Isolate the variable term

Subtract 4 from both sides of the equation.
$4 + 3x - 4 = 25 - 4$

Step2: Simplify both sides

Calculate the resulting values.
$3x = 21$

Answer:

$3x = 21$