Hi, i need with a practice sat question on math. the problem is in the picture.

  2.5

Step-by-step explanation:

The equation will have infinite solutions when it is a tautology--when both sides say exactly the same thing.

Eliminate parentheses, match coefficients, and solve for b.

  ax +ab = 4x +10

  a = 4 . . . . . . coefficient of x

  ab = 10 . . . . constant

Since we know a, we can find b:

  4b = 10

  b = 10/4 . . . . . . . divide by 4

  b = 5/2 = 2.5 . . .express in your favorite form

step-by-step explanation: