If 2x+1=8, then 4x+1=

We have align*2x+1 = 8 & 2x = 7 & x = 72,align* so align*4x+1 &= 4(72)+1 &= 2(7)+1 &= 15.align*

smc

prealgebra intermediate

Problem

2 x + 1 = 8

, then

4 x + 1 =

(A)

15

(B)

16

(C)

17

(D)

18

Solution

We have

2 x + 1 = 8 ⟺ 2 x = 7 ⟺ x = \frac{7}{2},

4 x + 1 = 4 (\frac{7}{2}) + 1 = 2 (7) + 1 = 15 .

Final answer