All categories

3 years ago

Solve: 2y + 5x=30 y = 3x + 4

1 answer:

6 0

Replace the second equation y=3x+4 into the first one:
2(3x+4)+5x=30
Now solve for x:
6x+8+5x=30
11x=30-8
11x=22
x=22/11
x=2
Finally, replace x=2 into y=3x+4
y=3*2+4
y=6+4 = 10
So the anwer is x=2, y=10

You might be interested in

Can any one tell me how to do this problem?

Vika [28.1K]

(1/2)/2=3/x
we can cross multiply, aka multiply both sides by 2x
(1/2)x=2*3
(1/2)x=6
times 2/1 both sides
x=12

5 0

3 years ago

What is the decimal representation of 1/8?

jarptica [38.1K]

Its A 0.125 because 0.125×8=1.000 or 1 full

6 0

3 years ago

What is this percent in simplest form? 15 3/5%=

Paul [167]

Answer:

0.156

Step-by-step explanation:

15 3/5%=(15+ 0.6)/100=15.6/100=0.156

5 0

3 years ago

Evaluate S5 for 300 + 150 + 75 + … and select the correct answer below. 18.75 93.75 581.25 145.3125

Savatey [412]

we have that

$300 + 150 + 75 +...$

Let

$a1=300\\ a2=150\\ a3=75$

we know that

$\frac{a2}{a1} =\frac{150}{300} \\\\ \frac{a2}{a1}=0.5 \\ \\ a2=a1*0.50$

$\frac{a3}{a2} =\frac{75}{150} \\\\ \frac{a3}{a2}=0.5 \\ \\ a3=a2*0.50$

$a(n+1)=an*0.50$

Is a geometric sequence

Find the value of $a4$

$a(4)=a3*0.50$

$a(4)=75*0.50$

$a(4)=37.5$

Find the value of $a5$

$a(5)=a4*0.50$

$a(5)=37.5*0.50$

$a(5)=18.75$

Find $S5$

$S5=a1+a2+a3+a4+a5\\ S5=300+150+75+37.5+18.75\\ S5=581.25$

therefore

the answer is

$581.25$

Alternative Method

Applying the formula

$S_n=\frac{a_1 (1-r^n)}{1-r} \\\\a_1=300 \\ r=\frac{1}{2}\\\\ S_5=\frac{300(1-(\frac{1}{2})^5)}{1-\frac{1}{2}}\\\\=\frac{300(1-\frac{1}{32})}{\frac{1}{2}}\\\\=\frac{300 \times \frac{31}{32}}{\frac{1}{2}}\\\\=\frac{75 \times \frac{31}{8}}{\frac{1}{2}}\\\\=\frac{\frac{2325}{8}}{\frac{1}{2}}\\\\=\frac{2325}{8} \times 2\\\\=\frac{2325}{4}\\\\=581 \frac{1}{4}\\\\=581.25$