Question 1121716
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The answer by the other tutor has errors; perhaps he will see my response and fix his....<br>
It is a useful skill, in a problem like this, to be able to get the answer to the question (the x^2 term in the expansion) without performing the entire multiplication.<br>
The first squared expression expands to {{{4+12x+9x^2}}}; the second to {{{16x^2+8x+1}}}.<br>
The x^2 term in the final product will come from (1) the product of the constant in the first of these and the x^2 term in the second; (2) the product of the x terms in each; and (3) the product of the x^2 term in the first and the constant in the second.  The coefficient is then<br>
{{{4(16)+12(8)+9(1) = 64+96+9 = 169}}}<br>
The x^2 term in the expansion is 169x^2.