Stuck in it from a week!! Help please.

Mathematics

1 answer:

nadya68 [22]4 years ago

5 0

The answer is 49 because x = 1/7 and 1/7^-2 =49

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2y + x + 7 = 0 how do i solve with substitution?

Jlenok [28]

Answer:

x+2y=-7

Step-by-step explanation:

2y + x =-7

x+2y=-7

6 0

3 years ago

Read 2 more answers

Code. -3x + 4y = -8 8x - y = 16 Solving systems by substitution

LiRa [457]

Answer:

The solution to the system of equations is $\displaystyle \big(\frac{56}{29}, -\frac{16}{29}\big)$ .

Step-by-step explanation:

We are given a system of equations:

$\displaystyle \left \{ {{-3x+4y=-8} \atop {8x-y=16}} \right.$

We need to solve these by substitution, so we need to solve one equation for a variable and then substitute the value of that variable into the other equation.
After doing this and solving for the opposite variable, we need to insert this into the original equation and solve for the initial variable.
Therefore, to solve one of the equations, we will solve it to put it in slope-intercept form and solve for y. The easier equation to work with is equation two.

$\displaystyle 8x - y = 16\\\\-y = -8x + 16\\\\\frac{-y}{-1}=\frac{-8x+16}{-1}\\\\y = 8x - 16$

Now, we've solved for y. So, we can substitute this into either equation and solve for x.

$\displaystyle -3x + 4(8x -16)=-8\\\\-3x + 32x - 64 = -8\\\\29x - 64 = -8\\\\29x = 56\\\\\frac{29x}{29}=\frac{56}{29}\\\\x = \frac{56}{29}$

Now, we substitute our value for x into one of the original equations and solve for y.

$\displaystyle 8\big(\frac{56}{29}\big)-y=16\\\\-y = 16 - 8\big(\frac{56}{29}\big)\\\\-y=\frac{16}{29}\\\\\frac{-y}{-1}=\frac{\frac{16}{29}}{-1}\\\\y = -\frac{16}{29}$