Answer:
w=10 cm
Explanation:
The formula for the volume of a rectangular prism is V=whl.
So in this case, the equation would be 1560=w·12·(w+3). Then, we can simplify this equation.
1. Divide 12 to both sides of the equation. 1560/12=130. The equation becomes 130=w(w+3).
2. Distribute w through the parentheses, the equation becomes 130=w²+3w.
3. Then, -130 from both sides of the equation, so we can get the quadratic: w²+3w-130=0.
4. Factor the quadratic. w²+3w-130=(w-10)(w+13).
5. (w-10)(w+13)=0. w=10 or w=-13. However, w is the width of a rectangular prism, can the width of a shape be negative? No. So we can ignore the solution w=-13. Therefore, w=10cm.
6. To make sure our answer is correct, let's substitute the values back into the volume of a rectangular prism formula: V=whl. w=10; h=12; l=10+3=13; V=10(12)(13)=120*13=1560 cm³. As a result, our answer is correct, w=10 cm.
Hope this helps, have a nice day.