Question
If $x + y = 8$ and $xy = 15,$ than $x^2 + y^2$
✓
Answer
$x^2 + y^2 = (x + y)^2 - 2xy$
$\Rightarrow x^2 + y^2 = (8)^2 - 2 \times 15$
$\Rightarrow x^2 + y^2 = 64 - 30$
$\Rightarrow x^2 + y^2 = 34$
$\Rightarrow x^2 + y^2 = (8)^2 - 2 \times 15$
$\Rightarrow x^2 + y^2 = 64 - 30$
$\Rightarrow x^2 + y^2 = 34$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
P is any point on the side BC of a $\triangle\text{ABC}.$ P is joined to A. If D and E are the midpoints of the sides AB and AC respectively and M and N are the midpoints of BP and CP respectively then quadrilateral DENM is:
→If $2^{-\text{m}}\times\frac{1}{2^{\text{m}}}=\frac{1}{4},$ then $\frac{1}{14}\bigg\{(4^\text{m})^{\frac{1}{2}}\Big(\frac{1}{5^{\text{m}}}\Big)^{-1}\bigg\}$ is equal to:
→- $\frac{1}{2}$
- $2$
- $4$
- $-\frac{1}{4}$
The Quadrilateral forms by joining the mid-points of the sides of a Quadrilateral PQRS, taken in order, is a Rhombus if:
Let ABC be a triangle of area 24 sq. units and PQR be the triangle formed by the mid-points of the sides of $\triangle\text{ABC}.$ Then the area of $\triangle\text{PQR}$ is:
→- 12sq. units
- 6sq. units
- 4sq. units
- 3sq. units
Between any two rational numbers there.
The radius of a hemispheical balloon increase from 6cm to 12cm as air is being pumped into it. The ratio of the surface areas of the ballons in two cases is:
- 1 : 4
- 1 : 3
- 2 : 3
- 1 : 2
The decimal representation of a rational number is:
- always terminating.
- either terminating or repeating.
- either terminating or non-repeating.
- neither terminating nor repeating.
The linear equation 3x - 5y = 15 has: