Respuesta :
Answer:
A) what did the student do wrong, explain why they are incorrect
B) Demonstrate and explain the correct way to answer the question.
Lauren says that two expressions 3x+4(2x+5) and 6x +5x +5 are equivalent. Simplify the expressions to determine whether or not Lauren is correct. Substitute a value for x to see if she is right.
3x+8x+20 = 6x+5x+5
11x+20 = 11x+5
She is wrong
Students answer: She is correct because both equal 11x +5. I substituted x=2 and got 27 for both
She is wrong because 27 will be the answer for ' 11x+5' only. The correct method should be
x=-15
Step-by-step explanation:
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➷ A) The student did not expand properly for the first expression
B) (3x + 4)(2x + 5) = 6x^2 + 15x + 8x + 20 = 6x^2 +23x + 20
6x^2 + 23x + 20 = 11x + 5
Substitute 2 in:
6(2)^2 + 23(2) + 20 = 90
11(2) + 5 = 27
Lauren is incorrect as both expressions do not equal each other. When 2 is substituted, only the second expression equals 27
✽
➶ Hope This Helps You!
➶ Good Luck (:
➶ Have A Great Day ^-^
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