If 2x + 7 = 15, what is the value of 4x - 3? — SAT

If $2x + 7 = 15$ , what is the value of $4x - 3$ ?

Answer: 13

To find the value of the expression, first solve the linear equation for the variable. Subtracting 7 from both sides of the equation yields

2x = 8

. Dividing both sides of the equation by 2 yields

x = 4

. Substituting this value back into the expression yields

4(4) - 3 = 16 - 3 = 13

. Alternatively, since

2x = 8

, multiplying both sides by 2 gives

4x = 16

. Subtracting 3 from both sides of this relation yields

4x - 3 = 16 - 3 = 13

Subtract 7 from both sides of the equation

2x = 8

To isolate the variable term on one side of the equation

Divide both sides by 2

x = 4

To solve for the variable

Substitute the value of the variable into the target expression

13

To find the final evaluated value requested by the question

Solving a linear equation in one variable and evaluating an expression

Question