Test 3 Section 3 #17 (grid-in) please

When you have a bunch of fractions like this, with different denominators, start by multiplying by the least common multiple to eliminate all the fractions. In this case, multiply through by 36, since that’s a multiple of 9, 4, and 12.

    \begin{align*}36\left(\dfrac{7}{9}x-\dfrac{4}{9}x\right)&=36\left(\dfrac{1}{4}+\dfrac{5}{12}\right)\end{align*}

Now just multiply carefully and you should be all good to solve for x:

    \begin{align*}4(7x)-4(4x)&=9(1)+3(5)\\28x-16x&=9+15\\12x&=24\\x&=2\end{align*}

Leave a Reply