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4 years ago

How to solve this using the elimination method

Mathematics

1 answer:

marishachu [46]4 years ago

7 0

10x+2y=18
10x-7y=-18
Multiply the second one by -1
-10x+7y=18
Then add the two equations
10x+2y=18
+-10x+7y=18
----------------
9y=36
y=4

Plug that back into one of the equations above and solve for x
10x+2y=18
10x+2(4)=18
10x+8=18
10x=10
x=1

so your answer is x=1 and y=4 or (1,4)

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$\begin{aligned}&f(x)=4 x^{2}+8 x+1 \\&-1=4 x^{2}+8 x \\&-1=4\left(x^{2}+2 x\right) \\&-1+1=4\left(x^{2}+2 x+1\right) \\&0=4(x+2)^{2} \\&0=(x+2)^{2} \\&0=x+2 \\&-2=x\end{aligned}$

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$\begin{aligned}&f(x)=4 x^{2}+8 x+1 \\&-1=4 x^{2}+8 x \\&-1=4\left(x^{2}+2 x\right) \\&-1+4=4\left(x^{2}+2 x+1\right) \\&3=4(x+2)^{2} \\&\frac{3}{4} =x+2)^{2} \\&\frac{\pm\sqrt3}{2} =x+2 \\&\frac{-2\pm\sqrt3}{2} =x\end{aligned}$

By solving the quadratic equation using completing the square method we got that Penelope should have added 4 to both sides instead of adding 1.

To learn more about quadratic equations visit : brainly.com/question/1214333

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