Question

Rob and Lila try to simplify 18 x 4² + (9 - 3)². Rob simplifies the expression and gets 360. Lila simplifies it and gets 324. Which student is correct? What error did the other student make?

Answer 1

Answer:

Lila is correct and Rob is incorrect because she apply wrong property.    

 $18 \times 4^2+(9-3)^2=324$            

Step-by-step explanation:

Given : Rob and Lila try to simplify  $18 \times 4^2+(9-3)^2$

Rob simplifies the expression and gets 360. Lila simplifies it and gets 324.

To find : which student is correct and what error did the other student.

Solution: First we simplify the expression:

$18 \times 4^2+(9-3)^2$

$=18 \times 16+(6)^2$

$=288+36$

$=324$

The solution of the expression is 324 which means Lila simplifies correct.

The mistake is found in Rob,

She simplify  $(9-3)^2$ like $9^2-3^2=81-9=72$ and she put this in equation

$18 \times 4^2+(9-3)^2$

$=18 \times 16+9^2-3^2$

$=288+72$

$=360$  which is totally in correct.

because $(a+b)^2=a^2+b^2+2ab$ she use wrong property.

Answer 2

Lila is correct. Rob is wrong because he multiplied 18*4^2 and he gets 288 and then he added 81 and subtracted 9 and that gave him 360.