Solve by the substitution method.

Mathematics

1 answer:

allochka39001 [22]3 years ago

5 0

Answer:

x = -5 and y = 8 is the solution for the given equations.

Step-by-step explanation:

We are given the following information in the question:

$7x + 2y = -19\\-5x + y = 33$

We have to use substitution method to solve the following equations in two variables.

$-5x + y = 33\\y = 33 + 5x\\\text{Putting this value of y in the first equation}\\7x + 2y = -19\\7x + 2(33+5x) = -19\\7x + 66+10x = -19\\17x = -85\\\\x = \displaystyle\frac{-85}{17} = -5\\\\y = 33 + 5x = 33 + 5(-5) = 33-25 = 8$

Thus, x = -5 and y = 8 is the solution for the given equations.

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Solve h = - 16t2 + 36 for the time t in seconds it takes for the height h to reach 0. Apply the square root method.

qwelly [4]

Step-by-step explanation:

I'm not sure what the square root method is, but I'm assuming that you factor.

This is how I would solve it:

$h = - 16 {t}^{2} + 36 \\ 0 = - 16 {t}^{2} + 36 \\ 0 = - 4(4 {t}^{2} - 9) \\ 0 = (2t - 3)(2t + 3) \\ t = \frac{3}{2} \\ t = - \frac{3}{2}$

Since time can't be negative, you rule out the -3/2.

Answer:

$t = \frac{3}{2}$

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