Use the grouping method to factor the polynomial in the box completely.
1 answer:
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Answer:
D. (10, 15)
Step-by-step explanation:
Hi there!
We are given the following system:
+y=20
x+4y=70
And we want to solve it (find the values of x and y).
Let's use substitution for this problem, where we will isolate one variable on one side, while the other side contains an expression with the other variable. Then, we use the expression to solve for the variable that the expression contains, then use the value of that variable to solve for the aforementioned isolated variable.
Subtract from both sides in the first equation
y=20-
Now substitute 20- as y in x+4y=70
x+4(20-)=70
Do the distributive property
x+80-2x=70
Combine like terms on the left
-x+80=70
Subtract 80 from both sides
-x=-10
Multiply both sides by -1
x=10
We found the value of x. Now let's use that value to find what y is
Since we know that y=20- and x=10, we can substitute 10 as the value of x to solve for y
In that case,
y=20-(10)
Multiply
y=20-5
Subtract
y=15
The answer is x=10, y=15, or as a point, <u>(10, 15), aka D</u>
Hope this helps!
Answer:
<em>C) 7</em>
Step-by-step explanation:
<u>Quadratic equation</u>
The quadratic equation can be written in several ways, one of the most-used is
To rewrite the equation in the form
we can complete squares and rearrange the terms as follows. The provided equation is
The second term can be seen as
And the first two terms can be visualized as the square of a binomial
We have added and subtracted 81 to complete the square and not modify the equation. The new form of the equation is
Rearranging
Comparing with the general form written above, we find that