I presume that this is talking about simplification with the rule of PEMDAS. First, look at the parenthesis and brackets. Let's do the [(7t + 5) - (8 - 3t)] part first. The parenthesis can go away on the inside if you distribute the negative in (8 - 3t), which flips the signs of those. You should then have [7t + 5 - 8 + 3t], then work it out to form just (10t - 3). The negative will also carry for the brackets that were there before, so - (10t - 3) turns into -10t + 3. Now, you just have 5t + t - 3 - 10t + 3. Work that out to get your final answer of -4t.
<span>Distribute of the Negative Sign: </span><span><span><span>5t</span>+t</span>−3</span>+<span><span>−1</span><span>(<span><span><span>7t</span>+5</span>−<span>(<span>8−<span>3t</span></span>)</span></span><span>) </span></span></span><span><span><span><span><span><span><span>5t</span>+t</span>+</span>−3</span>+<span><span>−1</span><span>(<span>7t</span>)</span></span></span>+<span><span>(<span>−1</span>)</span><span>(5)</span></span></span>+<span><span>(<span>−1</span>)</span><span>(<span>−8</span>)</span></span></span>+<span><span>−1</span><span>(<span>3t</span>)</span></span> <span><span><span><span><span><span><span><span><span><span>5t</span>+t</span>+</span>−3</span>+</span>−<span>7t</span></span>+</span>−5</span>+8</span>+</span>−<span>3<span>t </span></span>Now simple, Just Combine Like Terms: <span><span><span><span><span><span><span>5t</span>+t</span>+<span>−3</span></span>+<span>−<span>7t</span></span></span>+<span>−5</span></span>+8</span>+<span>−<span>3<span>t </span></span></span></span><span>(<span><span><span><span>5t</span>+t</span>+<span>−<span>7t</span></span></span>+<span>−<span>3t</span></span></span>)</span>+<span>(<span><span><span>−3</span>+<span>−5</span></span>+8</span><span>) </span></span>−<span>4<span>t </span></span> -4t would be the answer.
The first thing we are going to do for this case is to define the following variable: x = number of trees. We then have that the equation that represents the problem is given by: y = 50 (x-1) + 20 Rewriting: y = 50x - 50 + 20 y = 50x - 30 Substituting for y = 390 we have: 390 = 50x - 30 We clear x: x = (390 + 30) / (50) x = 8.4 nearest whole integer x = 8 Answer: will be planted along one block about 8 trees.
