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3 years ago

Solve the system by substitution. x – 4y = -8 5у – 1 = x Submit Answer

Mathematics

2 answers:

Vikki [24]3 years ago

7 0

Answer:

y = -7 and x = -36

Step-by-step explanation:

x - 4y = -8

5y - 1 = x

→ Substitute 5y - 1 into x - 4y = -8

5y - 1 - 4y = -8

→ Simplify

y - 1 = -8

→ Add 1 to both sides

y = -7

→ Substitute y = -7 into 5y - 1

( 5 × -7 ) - 1 = -36

S_A_V [24]3 years ago

5 0

Answer:

The solution is (-36, -7)

Step-by-step explanation:

Since 5y - 1 = x, we can replace x in the first equation by 5y - 1:

5y - 1 - 4y = -8

Collecting like terms, we get:

y = -7

If y = 7, then by the second equation x = 5(-7) - 1 = -36

The solution is (-36, -7)

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the length of a rectangle is 7 yd less than three times the width, and the area of the rectangle is 66 yd(squared). find the dim

Alex_Xolod [135]

So legnt=l
width=w
l=-7+3w
l=3w-7

area=66
area=legnth times width or
area=lw

subisutte
area=lw
l=3w-7
66=(3w-7)(w)
66=3w^2-7w
subtrac 66 from both sides
0=3w^2-7w-66
factor
HOW TO
multiply 3 and -66=-198
find what 2 numbers add up to -7 and multiply to get -198
the numbers area 11 and -18
so
3w^2-18w+11w-66=0
factor
(3w^2-18w)+(11w-66)=0
(3w)(w-6)+(11)(w-6)=0
factor using distributive (ab+ac=a(b+c))

(3w+11)(w-6)=0
set them to zero
3w+11=0
subtract 11
3w=-11
legnths cannot be negative so we discard this

w-6=0
add 6
w=6

width=6
legnth=3w-7
length=3(6)-7
legnt=18-7
legnth=11

width=6
legnth=11

7 0

3 years ago

Write a quadratic equation given the roots -1/3 and 5, show your work

Travka [436]

$\boxed{(x - a)(x - b) = 0}$

The equation above is the intercept form. Both a-term and b-term are the roots of equation.

$x = - \frac{1}{3} \\ x = 5$

These are the roots of equation. Therefore we substitute a = - 1/3 and b = 5 in the equation.

$(x + \frac{1}{3} )(x - 5) = 0$

Here we can convert the expression x+1/3 to this.

$x + \frac{1}{3} = 0 \\ 3x + 1 = 0$

Rewrite the equation.

$(3x + 1)(x - 5) = 0$

Simplify by multiplying both expressions.

$3 {x}^{2} - 15x + x - 5 = 0 \\ 3 {x}^{2} - 14x - 5 = 0$

Answer Check

Substitute the given roots in the equation.

$3 {(5)}^{2} - 14(5) - 5 = 0 \\ 75 - 70 - 5 = 0 \\ 75 - 75 = 0 \\ 0 = 0$

$3( - \frac{1}{3} )^{2} - 14( - \frac{1}{3}) - 5 = 0 \\ 3( \frac{1}{9} ) + \frac{14}{3} - 5 = 0 \\ \frac{1}{3} + \frac{14}{3} - \frac{15}{3} = 0 \\ \frac{15}{3} - \frac{15}{3} = 0 \\ 0 = 0$