How do work this out

Mathematics

1 answer:

BabaBlast [244]4 years ago

6 0

We can factor this by using grouping. Take the leading coefficient and multiply it by the constant. In this case we get 5*-7 = -35.

Now we need 2 numbers that add to 2 and multiply to be -35. The numbers are -5 and 7.

So split the 2r into these two terms and group.

(5r^2 - 5r) + (7r - 7)

Factor both groups.

5r(r-1) + 7(r-1)

The factors of (r-1) can be added together to get the answer.

(r-1)(5r+7)

You might be interested in

A baker made 20 pies. A Boy Scout troop buys one–fourth of his pies, a preschool teacher buys one–third of his pies, and a cater

n200080 [17]

Answer:

The number of pies does the baker have left is 15.

Step-by-step explanation:

Given : A baker made 20 pies. A Boy Scout troop buys one–fourth of his pies, a preschool teacher buys one–third of his pies, and a caterer buys one–sixth of his pies.

To find : How many pies does the baker have left?

Solution :

Let x be the number of pies does the baker have left.

According to question,

Number of pies buys,

One-fourth = $\frac{1}{4}$

One-third = $\frac{1}{3}$

One-sixth = $\frac{1}{6}$

i.e. $x=20-(20\times \frac{1}{4}+20\times \frac{1}{3}+20\times \frac{1}{6})$

$x=20-(5+20\times \frac{1}{3}+10\times \frac{1}{3})$

$x=20-(5+\frac{20+10}{3})$

$x=20-(5+ \frac{30}{3})$

$x=20-(5+10)$

$x=20-(15)$

$x=5$

The number of pies does the baker have left is 15.

7 0

3 years ago

Israel and Carlos were both eating at the same restaurant. Israel bought 4 hamburgers and 2 orders of fries for $9.74. Carlos bo

Likurg_2 [28]

Let
x-----------> cost of one hamburger
y-----------> cost of one order of fries

we know that
4x+2y=9.74--------------> equation 1
12x+y=22.77-----------> y=22.77-12x-----------> equation 2

using a graph tool---------> calculate the equations system
see the attached figure

the solution is
x=1.79
y=1.29

the cost of one hamburger is $1.79
the cost of one orders of fries is $1.29

If Tashiana buys 3 hamburgers and one order of fries
3*1.79+1.29---------> $6.66

the answer is $6.66