Lisa is seven times as old as her brother. She will be four times as old as her brother in three years. Represent the above situation in mathematical form.

Let B = the brothers age now

Let L = Lisa's age now

Then today:

L = 7B

And three years from now, Lisa's current age plus 3 equals 4 times the brothers age plus 3 represented by the following formula

L+3 = 4(B+3)

Now we can substitute the value of L in the first formula for L in the second formula

7B + 3 = 4(B+3)

So the answer is C

Step-by-step explanation:

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x