Answer:
x=-4, x=2
Step-by-step explanation:
Whenever a question asks you to find the zeros of a quadratic equation, they are essentially asking you to find the x-intercepts. To find the x-intercepts, you simply need to equate y to zero and solve for x.
There are two main ways to find the intercepts - by the quadratic formula and factoring. I will demonstrate both below.
When factoring, a popular method is the diamond box method. First, make an x on your paper. In the top nook of the x, write the product of a and c in y=ax^2 +bx +c. Here, it is -8*1=-8. In the bottom nook, write the b value. Here it is 2. Find two numbers that multiply to ac or -8 and add up to b or 2 and write them in the side nooks. In this problem, they are 4 and -2 (4*-2=-8 and 4+(-2)=2). Then, make a box. On the top left corner, write the first term (here it is x^2) and on the bottom right corner write the constant term (here it is -8) and write the two values you found earlier in the remaining boxes. Now, find values that multiply to each of the respective terms. Sorry, this sounds super confusing, I have included a picture below of what the result should look like. Once you have it factored, make y equal to zero and solve for both x's. You should get x=2 and x=-4. Keep in mind, sometimes, a problem might not be factorable. If it isn't, you have to use the method below.
Another popular way to find the roots is the quadratic formula. I have included a picture of it below. All you have to do is substitute the coefficients in and solve for x. You should get two solutions in this scenario.
22 houses can be cleaned in 11 hours.
Step-by-step explanation:
It is given that;
6 hours = 12 houses cleaned
1 hour =
1 hour = 2 houses cleaned
In 1 hour, 2 houses can be cleaned, therefore,
11 hours = Time*houses cleaned in one hour
11 hours = 11*2 =22 houses cleaned
22 houses can be cleaned in 11 hours.
Keywords: unit rate, multiplication
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