Question the-eq

1.2 Linear Equations in One Variable - Variables on both sides
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The equation 9 x plus 5, equals a, times, open parenthesis, x plus b, close parenthesis, where a and b are constants, has no solutions. Which of the following must be true?

I. a, equals 9

II. b equals 5

III. b is not equal to five ninths

A.

we only

B.

we and Iwe only

C.

we and IIwe only

D.

None

The equation , where a and b are constants, has no solutions. Which of the following

Hard-difficulty · SAT Math · Linear Equations in One Variable — Variables on both sides. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice D is correct. For a linear equation in a form a, x plus b, equals, c x plus d to have no solutions, the x-terms must have equal coefficients and the remaining terms must not be equal. Expanding the right-hand side of the given equation yields 9 x plus 5, equals, a, x plus a, b. Inspecting the x-terms, 9 must equal a, so statement we must be true. Inspecting the remaining terms, 5 can’t equal 9 b. Dividing both of these quantities by 9 yields that b can’t equal five ninths. Therefore, statement IIwe must be true. Since b can have any value other than five ninths, statement Iwe may or may not be true.

Choice A is incorrect. For the given equation to have no solution, both a, equals 9 and b is not equal to five ninths must be true. Choice B is incorrect because it must also be true that b is not equal to five ninths . Choice C is incorrect because when a, equals 9 , there are many values of b that lead to an equation having no solution. That is, b might be 5, but b isn’t required to be 5.