8n+7=31 what does n equal

Mathematics

2 answers:

shusha [124]3 years ago

7 0

Answer: n = 3

Step-by-step explanation:

oksano4ka [1.4K]3 years ago

6 0

Answer:

Step-by-step explanation:

take the 7 and minus it from 31 then divide 8 from 31

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The three sides of a triangle are 4cm, 6cm and 8cm.

yarga [219]

Answer:

In bold below.

Step-by-step explanation:

(a) The largest angle is opposite the largest side.

So by the Cosine Rule:

8^2 = 4^2 + 6^2 - 2*4*6 cos x

cos x = (8^2 - 4^2 - 6^2) / (-2*4* 6)

= -0.25.

x = 104.48 degrees.

(b) Area of the triangle = 1/2 * 4 * 6 sin 104.48

= 11.62

= 3 √15.

Area = 1/2 * altitude * base

3√15 = 1/2 * 8 * a

a = 3√15 / 4 cm

= 0.75√15 cm.

6 0

4 years ago

Quadratic Formula to solve the equation x^2- 4x = - 7

mylen [45]

roots of the equation x^2- 4x = - 7 are 2+3i and 2-3i

What are the natures of root of quadratic equation?

Case I: $4ac > b^2$

The roots of the quadratic equation $ax^2 + bx + c = 0$ are real and unequal when a, b, and c are real numbers, a 0, and the discriminant is positive.

Situation II: $b^2$ $-4ac$ =0

The roots and of the quadratic equation $ax^2 + bx + c = 0$ are real and equal when a, b, and c are real numbers, a 0, and the discriminant is zero.

Case III: $b^2$ $-4ac$ <0

The quadratic equation $ax^2 + bx + c = 0$ has roots when a, b, and c are real numbers, a 0, and the discriminant is negative, but these roots are not equal and are not real. We refer to the roots in this instance as fictitious.

Case IV: Perfect square and $b^2 - 4ac > 0$

The roots of the quadratic equation $ax^2 + bx + c = 0$ are real, rational, and unequal when a, b, and c are real numbers, a 0, and the discriminant is positive and perfect square.

Quadratic Formula $x={\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}$