<p>I need help with this type of questions. </p>
<p>If 2a+b=6 and 4a^2 - b^2=54, what is the value of 2a-b ? (Grid in) </p>
<p>The answer is 9.</p>
<p>4a^2-b^2=(2a-b)(2a+b)=54
(2a-b)6 = 54
2a-b= 54/6= 9</p>
<p>thanks, I appreciate it !</p>
<ol>
<li>4a^2 - b^2 = 54</li>
<li>2a + b = 6
Divide like terms in equation 1 by like terms equation 2 and you get:
2a - b = 9</li>
</ol>
<p>That another helpful way , thanks a lot!</p>